--- title: Selections from Ibn Sina’s Canon of Medicine description: "# **Classical Islamic medicine** ## **Selections from Ibn Sina’s Canon of Medicine** #### **Structure and terminology of the work:** Kitāb (كتاب) → Book Fann (فنّ) → Concentration (or specialization) Taʿlīm (تعليم) → Instruction Faṣl (فصل) → Section --- ### **Introduction**…" url: "https://majalla.org/ilm/selections-from-ibn-sinas-canon-of-medicine/" updated: "2025-10-24" category: Medicine tags: - Health --- # Selections from Ibn Sina’s Canon of Medicine # **Classical Islamic medicine** ## **Selections from Ibn Sina’s Canon of Medicine** #### **Structure and terminology of the work:** Kitāb (كتاب) → Book Fann (فنّ) → Concentration (or specialization) Taʿlīm (تعليم) → Instruction Faṣl (فصل) → Section --- ### **Introduction** Praise be to God with the kind of praise befitting His exalted station and abundant grace, and blessings upon our Master Muḥammad the Prophet and his family. To proceed: Some of my sincere companions, whose request I am bound to fulfill to the extent of my ability, asked me to compose a book on medicine, one that would encompass both its general and particular principles, combining explanation with conciseness, and fulfilling the requirements of clarity while maintaining brevity. I have granted this request. I deemed it proper to begin with the general, universal aspects of medicine in both of its branches: the theoretical and the practical. Then, I shall speak of the universal principles concerning the properties of simple medicaments, followed by their particulars. After that, I will treat of diseases that occur in specific organs, starting each time with a discussion of the anatomy and function of the organ in question. As for the anatomy and functions of the simple, individual organs, I would have already mentioned these in the first general book. Once the anatomy of a particular organ is addressed, I will proceed, in most instances, by discussing how to maintain its health. Then I will present, in general terms, the universal categories of its diseases, their causes, the signs by which they are recognized, and the general principles of their treatment. Once I complete these universal matters, I will turn to particular diseases, and in most cases will begin by presenting the general ruling concerning each disease’s definition, cause, and signs, before proceeding to their specific treatments. I will then present the general rule (qānūn kullī) for therapy, and from there descend to particular therapies involving individual or compound medicaments. As for what I have already written about simple drugs and their benefits for certain diseases in the Book of Simple Drugs—in tables and dye formulas that I have indicated should be used—I will not repeat it here except where absolutely necessary. And as for compound drugs, the proper place for their formulation and therapeutic uses is in the *Aqrabādhīn* (pharmacopoeia), which I intend to compile separately. I have postponed the discussion of their uses and combinations until that time. I also decided to complete this current book with another that deals with particular matters—specifically, diseases that do not pertain to any one organ in particular. In that book, I will also discuss cosmetics (*zīnah*), and I will follow the same method in its structure as I do in the current volume. If, by the grace of God Most High, I am enabled to complete this book, I will follow it with the *Aqrabādhīn*. This is a book that no one who claims to practice this art—medicine—and who makes a livelihood from it, can afford to be ignorant of or fail to preserve in memory. For it contains the minimum knowledge absolutely essential for a physician. Anything beyond it falls under the category of supplemental knowledge that varies and is without strict bounds. If God Most High prolongs my life and fate permits, I will undertake this task again with renewed resolve. For now, I divide this book into five treatises, as follows: 1. The First Book: On the general principles of the science of medicine. 2. The Second Book: On simple drugs (*al-adwiyah al-mufradah*). 3. The Third Book: On particular diseases that affect the human body organ by organ, from head to foot, both externally and internally. 4. The Fourth Book: On particular diseases that do not pertain to any specific organ, and on cosmetics (*zīnah*). 5. The Fifth Book: On the composition of medicines—that is, the *Aqrabādhīn*. --- **Book One:** ## **On the General Principles of the Science of Medicine** This book consists of four disciplines (funūn).   **Discipline One: On the Definition and Subjects of Medicine among the Natural Sciences** This section includes six teachings (*ta**ʿ**ā**l**ī**m*).   **Teaching One:** **Comprising Two Chapters** **Chapter One:** I say: Medicine (*ṭ**ibb*) is the science by which one learns the conditions of the human body in terms of what preserves health and what causes its departure, so that health may be maintained when present and restored when lost. Now, someone may object: "Medicine is divided into theory and practice. But you have defined it entirely as a theoretical science by saying it is a 'science' — have you not ignored the practical side?" To this, we respond: It is said of the sciences in general that some are purely theoretical, some practical, and some a mixture of both. Similarly, it is said that philosophy includes both theoretical and practical branches, and likewise medicine includes both. But in each domain, the terms 'theoretical' and 'practical' mean different things. We need not discuss these distinctions in every field right now, only as they pertain to medicine. So, when it is said that medicine includes both theory and practice, it should not be imagined—as many researchers wrongly suppose—that medicine consists of two separate fields, one purely speculative and the other purely operative. Rather, the proper view is that one part of medicine concerns the foundational principles (*uṣūl*) of the science, and the other part concerns the manner in which those principles are applied. The first is called ‘knowledge’ (*ʿ**ilm*) or ‘theory’ (*na**ẓ**ar*), and the second is called ‘practice’ (*ʿ**amal*). By ‘theory’ we mean: instruction that is limited to knowledge and belief, without specifying how to act — for example, in medicine: “there are three types of fevers” or “there are nine kinds of temperaments.” By ‘practice’ we do not mean manual labor or bodily movements, but rather that part of medical science whose instruction leads to an opinion (*ra**ʾ**y*) that pertains to how something ought to be done — such as: “in treating hot swellings, one must begin by applying cooling, astringent, and dispersing agents; then combine astringents with relaxants; and when the swelling subsides, continue only with resolvent relaxants—unless the swelling is caused by material expelled from a major organ.” Such instruction provides a judgment: it shows how something ought to be done. When you comprehend both of these parts, you possess both the theoretical and the practical knowledge of medicine—even if you never personally engage in the practice.   No one can object by saying: “The states of the human body are three: health, illness, and a third state that is neither.” And yet you mention only two. This objector, if he reflects, may realize that neither the tripartite nor the bipartite division is strictly necessary. And even if the tripartite view were obligatory, our statement “departure from health” includes both illness and the third state—since health is a condition or capacity by which the body performs its functions properly, and anything that departs from that condition—whether it is defined as disease or not—is outside of health. Thus, there is no reason to argue with physicians on this matter. They are not concerned with philosophical debates, and such arguments yield no practical benefit in medicine. As for discerning the ultimate truth of this question, that belongs to the discipline of logic (*man**ṭ**iq*), and should be sought there. **Chapter Two:** ## **On the Subject Matter of Medicine** Since medicine investigates the human body in terms of what maintains health and what causes its departure, and since knowledge of anything is only possible through knowledge of its causes, it is necessary in medicine to know the causes of health and disease. Health and disease and their causes may be either apparent (perceptible to the senses) or hidden (discerned only through inference from symptoms). Thus, the physician must also know the symptoms (*ʿ**awāri**ḍ*) that occur in states of health and disease. It has been established in the real sciences (*ʿ**ulūm**ḥ**aqīqiyyah*) that knowledge of a thing is acquired either by understanding its causes and principles—or, if those are not available, through its symptoms and essential attributes. There are four types of causes: 1. **Material causes** (*asbāb māddiyyah*): These are the substrates in which health or disease exists. The nearest subject is the organ or the vital spirit (*rū**ḥ*), and the more remote are the humors (*akhlā**ṭ*), and more remote still are the elemental components (*arkān*). 2. **Efficient causes** (*asbāb fā**ʿ**iliyyah*): These are the agents that preserve or alter the body’s condition—such as the air and its qualities, food and drink, evacuation and retention, locales and dwellings, bodily and psychic movements (including sleep and wakefulness), transformations over time (like changes with age), and environmental factors like customs, occupations, and other external factors that come into contact with the body either naturally or unnaturally. 3. **Formal causes** (*asbāb ṣūriyyah*): These are the temperaments (*amzijah*), the powers (*quwá*) that arise from them, and the structural arrangements. 4. **Final causes** (*asbāb tamāmiyyah*): These are the actions and functions. Knowledge of these actions necessarily involves knowledge of the powers, and knowledge of the powers depends on knowledge of the spirits (*arwā**ḥ*) that carry them—as will be discussed. These are the objects of study in medicine insofar as it investigates how the body becomes healthy or ill. But to complete the purpose of medicine—namely, the preservation of health and the removal of illness—one must also study the means and tools by which this is done. These include food and drink, the selection of air, the regulation of motion and rest, drug therapy (*ʿ**ilāj bi’l-dawā**ʾ*), and manual therapy (*ʿ**ilāj bi’l-yad*). All of this is classified by physicians under three categories of patients: the healthy, the sick, and those of intermediate condition (whom we will define and explain, including how they are "intermediate" between two opposing states in name, though not always in reality). By laying out these considerations, we conclude that the scope of medicine includes study of: - The elements (*arkān*), - The temperaments (*amzijah*), - The humors (*akhlā**ṭ*), - The simple and composite organs, - The spirits (*arwā**ḥ*), - The natural, vital, and psychic faculties, - The actions (*af**ʿ**ā**l*), - The bodily states of health, illness, and the intermediate condition, and their causes, - The roles of food, drink, air, water, geography, dwellings, evacuation, retention, occupation, customs, movements (bodily and psychic), rest, age, constitution, and external influences, - The regimens and treatments used to preserve health and treat disease. Some of these matters the physician must simply understand by their essence (*māhiyyah*), trusting their soundness as inherited from natural philosophy. Others he must prove and demonstrate within his medical art. The foundational principles (such as the nature of the elements, temperaments, humors, and powers) must be accepted as givens from higher sciences, especially natural philosophy (*ʿ**ilm al-**ṭ**abī**ʿ**iyy**ā**t*), until they ultimately ascend to first philosophy (*al-**ḥ**ikmah al-ūlá*, metaphysics). When a practitioner of medicine begins to debate the existence of the elements, or the reality of temperament, and such matters that are the proper domain of natural philosophy, he errs in two ways: 1. He introduces into medicine what properly belongs to another science. 2. He supposes that he has clarified something when in fact he has not. Therefore, the physician must accept as essential knowledge the following: - That the elements exist, what they are, and how many they are; - That temperaments exist, what they are, and how many they are; - That humors exist, what they are, and how many they are; - That powers exist, and how many there are; - That spirits exist, how many there are, and where they are found; - That every change has a cause; - That causes are of various kinds. As for the organs and their functions, the physician must perceive them through direct observation and dissection. What he must understand and demonstrate, however, are the particular diseases, their causes, their signs, and the means of restoring health—especially those conditions whose existence is subtle and not obvious to the senses. When Galen sought to prove the first set of matters (such as the elements), he did so not as a physician, but as a philosopher engaging in natural science. Similarly, when a jurist (*faqīh*) attempts to prove the obligation of following consensus (*ijmā**ʿ*), he does so not in his capacity as a jurist, but as a theologian (*mutakallim*). Therefore, the physician—**as physician**—cannot independently prove these metaphysical matters. Otherwise, a logical fallacy (*dawr*) would occur.   **Teaching Two** **On the Elements (*al-Arkān*)** **[A Single Chapter]** The *arkān* (elements) are simple bodies—basic constituents of the human body and other organisms. They are indivisible into parts that differ in form. These are the components into which all compounds decompose, and by their intermixing arise the various types and forms of created beings. Let the physician accept from the natural philosopher that they are **four only**: two of them are light (*khafīfān*), and two heavy (*thaqīlān*). The light elements are: - **Fire** (*nār*) - **Air** (*hawā**ʾ*) The heavy elements are: - **Water** (*mā**ʾ*) - **Earth** (*ar**ḍ*) **Earth** is a simple substance, whose natural place is the center of the cosmos. It remains stationary there by nature, and if removed, it moves back there naturally. That is its **absolute heaviness**. Its nature is **cold and dry**—that is, its inherent property when left to itself and not altered by external causes—whereby coldness and dryness become apparent. Earth’s presence in bodies serves the function of **firmness, stability, and preservation of shape and form**. As for **Water**, it is also a simple substance. Its natural place is to surround Earth and be surrounded by Air, when both are in their natural positions. Its heaviness is **relative**. Its nature is **cold and moist**—that is, in its original state it responds quickly to separation and union, accepting any form but not retaining it. Its role in the body is to assist in the **malleability of forms**, shaping and smoothing structures. While moisture (*ru**ṭ**ūbah*) makes matter easily shaped, it also causes it to easily lose form. Conversely, dryness (*yubūsah*) makes matter hard to shape but also good at retaining form. When dry matter is softened by moisture, it gains **pliability and the ability to be shaped**, while moisture gains from dryness **the ability to retain the shape given to it**. So the dry binds the moist, and the moist prevents the dry from scattering. **Air** is a simple substance whose natural place is **above water and below fire**—this defines its **relative lightness**. Its inherent nature is **hot and moist**, according to the principles mentioned. Its function in the body is to provide **lightness, porosity, and expansion**—allowing the body to be more mobile and active. As for **Fire**, it is a simple substance whose natural place is above all other elemental bodies, at the **concave boundary of the celestial sphere**, where **generation and corruption cease**. This is its **absolute lightness**. Its nature is **hot and dry**. Its function in bodies is to **cook, refine, and combine** materials. It moves through the body by permeating the airy substance and serves to **moderate the extreme coldness** of the heavy, cold elements (water and earth), thus transforming them from a purely elemental state to a tempered (*mizājī*) one. Thus, **the heavy elements** assist in the **formation and stability of the organs**, and their stillness. While **the light elements** assist in the **generation and movement of the vital spirits**, and in the activation of the organs. Even so, the **first mover** (*al-mu**ḥ**arrik al-awwal*) is the **soul** (*nafs*), by the permission of its Creator. **These, then, are the Elements.** --- **Teaching Three** ## **On Temperaments (*al-Amzijah*)** **[Comprising Three Chapters]**   **Chapter One:** ## **On the Definition of Temperament** I say: Temperament (*mizāj*) is a **quality resulting from the interaction** of opposing elemental qualities (*kayfiyyāt mu**ḍ**āddah*)—namely heat, coldness, moisture, and dryness—when these meet and reach a balanced point of interaction. This interaction occurs within the **minute parts** of each element so that the finest parts of one may contact the finest parts of the other. When their inherent powers (*quwá*) act upon one another, and these actions permeate all parts involved, a **new uniform quality** emerges across the whole—this is what we call *mizāj* (temperament). The four **primary qualities** in the elements mentioned above are: - Heat (*ḥ**arārah*) - Coldness (*burūdah*) - Moisture (*ru**ṭ**ūbah*) - Dryness (*yubūsah*) It has been established that **all physical bodies** (*ajsām kā**ʾ**inah f**ā**sidah*)—those subject to generation and corruption—derive their temperaments from these qualities, in accordance with what rational division (*al-qismah al-**ʿ**aqliyyah*) necessitates. There are two main logical possibilities: 1. **Moderate Temperament** (*mizāj mu**ʿ**tadil*): This arises when the **proportions** of the opposing qualities in the mixture are **equal** and in **mutual equilibrium**. In this case, the resulting temperament is a **perfect mean** between them. 2. **Imbalanced Temperament** (*mizāj mā**ʾ**il*): This occurs when the resulting quality **leans toward one of the extremes**—either: - In **one dimension only**: between heat and cold, or moisture and dryness; or - In **both dimensions simultaneously**. However, the balance or imbalance recognized in the medical profession is **not exactly this**. Rather, the physician must receive from the natural philosopher the understanding that **perfect moderation**—as defined strictly by equal balance—is **impossible** to find in actuality, much less in any human body or organ. Instead, what physicians mean by a “moderate temperament” (*al-mu**ʿ**tadil*) in their practical discussions is a **derivative concept**—not absolute balance, but the **most just proportion** suitable to the human body or organ, according to its optimal function and structure. This ideal is not the metaphysical *mu**ʿ**tadil* of philosophical speculation, but rather the **best possible practical proportion**. It may happen that this practical moderation closely approximates the **true theoretical moderation**, and this is what physicians refer to as the *mu**ʿ**tadil mu**ʿ**tabar*—the “considered moderation” as it pertains to human bodies. Thus, the standard of *i**ʿ**tid**ā**l* (moderation) is relative to **human physiology** and **individual constitutions**, not to pure theoretical symmetry. This **practical moderation**—the one relevant to real human bodies—can be evaluated from **eight perspectives**, such as: - Comparison by **type** (*naw**ʿ*) with other types, - Comparison within the **same type** but among differing cases, - And other relative measures of balance. So even if an individual temperament is not **exactly at the center**, it can still be considered **moderate** in relation to others or to a defined physiological standard.   --- **Chapter Two:** ## **On the Varieties of Temperament** Temperaments vary according to the **dominance of one or more of the four elemental qualities**. These variations are categorized based on their inclination (*mayl*) toward heat, cold, moisture, or dryness, either **singly** or **in combination**. There are **nine principal types** of temperament: 1. **Moderate** (*Mu**ʿ**tadil*) – balanced in all four qualities. 2. **Hot only** (*ḥ**ārr faqa**ṭ*) 3. **Cold only** (*bārid faqa**ṭ*) 4. **Moist only** (*ra**ṭ**b faqa**ṭ*) 5. **Dry only** (*yābis faqa**ṭ*) 6. **Hot and moist** (*ḥ**ārr ra**ṭ**b*) 7. **Hot and dry** (*ḥ**ārr yābis*) 8. **Cold and moist** (*bārid ra**ṭ**b*) 9. **Cold and dry** (*bārid yābis*) These compound temperaments are more commonly found in **actual bodies**, whereas the purely single ones are **theoretical or rare** in real physiology. Moreover, the **dominant temperament** of a person or an organ depends on: - **Nature of the composite elements** involved, - **Proportions** of the qualities, - **Degree of influence** each quality exerts. So, while two individuals may both be labeled as having a “hot and moist” temperament, one might be **more hot than moist**, and the other **more moist than hot**—making their actual constitutions and medical needs **distinct**. **Chapter Three:** ## **On the Causes of Temperament Differences** Differences in temperament arise from: - The **material composition** of the body, i.e., the relative amount and nature of the humors (*akhlā**ṭ*), - The **influences** of the surrounding environment: such as air, season, region, or diet, - The **age** of the person (since temperament changes with time), - The **sex** of the person (men are generally drier and hotter, women moister and cooler), - The **occupation** or habitual activity, - Emotional states and psychic dispositions. For example: - Youth tends toward **hot and moist**; - Old age tends toward **cold and dry**; - The temperament of men generally leans toward **dryness and heat**; - Women’s temperaments tend more toward **moisture and coldness**. Understanding these variations is essential for diagnosis and treatment. A remedy that is suitable for one type of temperament may be **harmful or ineffective** for another. Thus, **correct evaluation of the patient’s temperament** is the foundation for: - Choosing appropriate food and drink, - Determining treatment plans, - Applying preventive measures, - And prescribing compound or simple medicaments.   With this, **Teaching Three on Temperaments** is now complete.   **Teaching Four** ## **On the Humors (*al-Akhlā******ṭ*****)** **Chapter One:** ### **On the Nature of the Humors** I say: The humors (*akhlā**ṭ*) are **substances generated from food** after it is digested in the stomach and liver, and they circulate in the body through the vessels, providing nourishment to the organs. They are **four in kind**, each corresponding to one of the elemental qualities, and they serve both physiological and pathological roles in the body. These four are: 1. **Blood** (*dam*) — Hot and moist 2. **Yellow bile** (*ṣafrā**ʾ*) — Hot and dry 3. **Black bile** (*sawdā**ʾ*) — Cold and dry 4. **Phlegm** (*balgham*) — Cold and moist Each of these humors corresponds in a certain way to one of the **elements**: - Blood to **air** (hot and moist) - Yellow bile to **fire** (hot and dry) - Black bile to **earth** (cold and dry) - Phlegm to **water** (cold and moist) The **balanced mixture** of these humors sustains health, while an **excess, deficiency, or corruption** in any of them leads to disease.   **Chapter Two:** ### **On the Generation of the Humors** The humors are generated during the **digestive process**, which occurs in **four stages**: 1. **Gastric digestion** (*al-hadm al-ma**ʿ**id**ī*) — where food is transformed into *chylous* matter (a kind of nutritional pulp) in the stomach. 2. **Hepatic digestion** (*al-hadm al-kabadī*) — where the chyle is converted into humors in the liver. 3. **Vascular digestion** — where the humors are refined further as they pass through the veins. 4. **Organic digestion** — where the humors nourish the specific tissues of the organs. Each stage refines the material further, and in each stage, a degree of **residue or waste** is produced—this too must be eliminated to maintain health.   **Chapter Three:** ### **On the Functions and Disorders of Each Humor** Each humor has a **natural function**: - **Blood** nourishes and supports vitality. - **Yellow bile** thins and cleanses the blood, stimulates appetite, and aids digestion. - **Black bile** provides density and structure to the body, and stabilizes temperament. - **Phlegm** lubricates, cools, and softens. When each is present in the **right proportion** and **correct quality**, the body remains in a state of equilibrium. But when a humor becomes: - **Too abundant**, - **Corrupted** in quality, - Or **displaced** to a part of the body where it should not be— —then illness arises. For example: - Excess blood causes fullness, heaviness, headaches, and skin eruptions. - Excess yellow bile may cause heat in the stomach, bitterness in the mouth, restlessness, and irritability. - Excess black bile may lead to melancholy, fear, or hardness of organs. - Excess phlegm may result in lethargy, cold limbs, and sluggish digestion. Therefore, the **regulation of the humors**—through diet, exercise, purgation, and medication—is the **core task** of the physician. This concludes **Teaching Four** on the Humors.   **Teaching Five** ## **On the Faculties (*al-Quwā*) of the Body** **Chapter One:** ### **On the Definition and Division of Faculties** I say: **Faculties** (*quwā**ʾ*) are the internal principles or capacities by which the body performs its vital operations. They are not bodies themselves, but rather **inherent powers** that reside in organs and function through them. These faculties are recognized through the **effects they produce**, and their presence is inferred from the actions observed. The **faculties** are commonly divided into three main categories: 1. **Natural Faculty** (*al-quwwah al-**ṭ**abī**ʿ**iyyah*) 2. **Vital Faculty** (*al-quwwah al-**ḥ**ayawāniyyah*) 3. **Psychic Faculty** (*al-quwwah al-nafsāniyyah*) Each of these corresponds to a **particular spirit** (*rū**ḥ*) and organ, and each has a unique set of functions and attributes. **Chapter Two:** ### **On the Natural Faculty** The **Natural Faculty** is seated primarily in the **liver**, and is responsible for: - **Nutrition** (*ghidhā**ʾ*), - **Growth** (*numuw*), - **Reproduction** (*tawlīd*). It governs the processes of digestion, transformation of food into humors, and the generation of semen and menstrual blood. The **spirit** associated with this faculty is the **natural spirit** (*al-rū**ḥ**al-**ṭ**abī**ʿ**ī*), which circulates with the humors, especially in the blood.   **Chapter Three:** ### **On the Vital Faculty** The **Vital Faculty** is seated in the **heart**, and is responsible for: - **Circulation of the vital spirit** (*al-rū**ḥ**al-**ḥ**ayawānī*), - Maintenance of **life and heat**, - Coordination of **heartbeat and pulse**. This faculty is what gives the body vitality and motion. It is carried through the **arterial system**, and its presence is perceived in the **pulse**. The **vital spirit** originates in the heart and is dispersed to all parts of the body through the arteries. Its purity and movement are essential to life.   **Chapter Four:** ### **On the Psychic Faculty** The **Psychic Faculty** is seated in the **brain**, and governs: - **Sensation** (*ḥ**iss*), - **Voluntary motion** (*ḥ**arakah irādiyyah*), - **Imagination**, **memory**, and **thought**. It operates through the **nerves**, which branch from the brain and spinal cord to all parts of the body. The **psychic spirit** (*al-rū**ḥ**al-nafsānī*) is the most subtle and refined of the spirits. It is generated in the brain from the vital spirit, and is transmitted through the nerves. This faculty allows humans to: - Perceive the external world, - Respond with movement and intention, - Think, remember, and plan.   **Chapter Five:** ### **On the Relationship Between Faculties and Organs** Each faculty resides in a **specific principal organ**, but acts throughout the body via **instrumental organs**: - The liver is the source of the natural faculty and sends it via the **veins**. - The heart is the source of the vital faculty and sends it via the **arteries**. - The brain is the source of the psychic faculty and sends it via the **nerves**. The **interdependence** of these faculties is essential: - The brain depends on the heart for vital heat. - The heart depends on the liver for nourishment. - The liver depends on the brain for regulation of motion and control. Disruption in any of these faculties—either through damage to the organ, corruption of the associated spirit, or imbalance in temperament—leads to dysfunction and disease. This concludes **Teaching Five** on the faculties of the body.   **Teaching Six** ## **On the Actions (*al-Af******ʿ******ā******l*****) of the Body** **Chapter One:** ### **On the Definition of Action and Its Relation to Faculty** I say: An **action** (*fi**ʿ**l* or *ʿ**amal*) is the effect that issues from a **faculty** (*quwwah*) through a particular **organ**, as part of the body's operations. Each faculty produces actions suitable to its nature, and the presence of the action is what indicates the existence and strength of the faculty. The relation among **faculty, spirit, and organ** is foundational: - The **faculty** is the cause (*ʿ**illah*) of the action, - The **spirit** is the medium or vehicle (*wāsi**ṭ**ah*), - The **organ** is the instrument (*ālah*) by which the action is executed. This triad must be in harmony for the action to occur properly. If any of the three—faculty, spirit, or organ—is deficient or damaged, the action will be defective or absent. **Chapter Two:** ### **On the Types of Actions** Actions of the body are divided according to the **faculties** from which they arise: 1. **Natural Actions** (*af**ʿ**ā**l**ṭ**abī**ʿ**iyyah*): These include digestion, assimilation, growth, reproduction, and formation of humors. They are carried out by the natural faculty, mainly via the liver and its extensions. 2. **Vital Actions** (*af**ʿ**ā**l**ḥ**ayawāniyyah*): These include heartbeat, pulse, generation and distribution of heat, and life maintenance. They stem from the vital faculty rooted in the heart and disseminated through the arteries. 3. **Psychic Actions** (*af**ʿ**ā**l nafs**ā**niyyah*): These are sensation (such as vision, hearing, taste, smell, touch), voluntary motion, thought, memory, imagination, and judgment. They are produced by the psychic faculty located in the brain and transmitted via the nerves. Each of these actions has a **proper subject**: - Digestion occurs in the **stomach**, - Pulse in the **arteries**, - Sight in the **eyes**, - Thinking in the **brain**, - and so forth. **Chapter Three:** ### **On the Signs of Proper and Deficient Action** By examining the quality of the body’s actions, one can determine the **state of the underlying faculties and organs**: - If an action is performed strongly and without pain, the faculty and organ are presumed sound. - If the action is weak, excessive, irregular, or absent, then there is likely a deficiency, corruption, or obstruction in the faculty, the organ, or the spirit that connects them. This method—**inferring internal conditions from external actions**—is one of the foundations of medical diagnosis. Examples: - Weak digestion may point to an imbalance in gastric temperament or a failure of the natural faculty. - Irregular pulse may indicate disruption of the vital spirit or obstruction in the arteries. - Hallucination or forgetfulness may suggest disturbance in the psychic faculty or dryness in the brain. Thus, knowledge of **actions** is not only important for understanding physiology, but is also **indispensable in clinical practice**. **Chapter Four:** ### **On the Goal of Studying Actions** The study of actions allows the physician to: - Recognize what is **natural** versus **abnormal** in the body, - Evaluate the **strength or weakness** of faculties, - Diagnose diseases and their **location, cause, and severity**, - Prescribe appropriate therapies based on which actions need to be **restored, supported, or restrained**. In this way, the science of actions (*ʿ**ilm al-af**ʿ**ā**l*) completes the physician’s understanding of the body as a **living, dynamic system**, composed of matter (*māddah*), form (*ṣūrah*), faculties (*quwā*), spirits (*arwā**ḥ*), and purposeful actions (*af**ʿ**ā**l*).   This concludes **Teaching Six** and completes **Discipline One** of **Book One**: the foundational theoretical framework of the science of medicine.   --- **Discipline Two** ## **On the General Principles Governing the Powers of Simple Medicaments** (*fī kulliyyāt a**ḥ**kām quwā al-adwiyah al-mufradah*) **Chapter One:** ### **On the Definition of Medicament and Its Active Power** I say: A **simple medicament** (*dawā**ʾ**mufrad*) is any substance whose composition consists of **a single essential nature** (*ṭ**abī**ʿ**ah w**ā**ḥ**idah*), and which, when applied to the body—either internally or externally—produces a change in its state by virtue of its inherent **temperament** (*mizāj*) or **active quality** (*kayfiyyah fā**ʿ**ilah*). The **power** (*quwwah*) of the medicament is what brings about this change. This power can be: - **Heating** (*mu**ḥ**arrir*), - **Cooling** (*mubarrid*), - **Moistening** (*murattib*), - **Drying** (*mujaffif*), —each corresponding to one of the four elemental qualities. Thus, a medicine may be described as “hot in the first degree,” or “cold and dry in the second degree,” and so forth—based on its **effect on the body**, not on its own inherent temperature as perceived by the senses.   **Chapter Two:** ### **On How to Determine the Power of a Medicament** The power of a medicament is determined through **three main approaches**: 1. **Sensation** (*ḥ**iss*): By the taste, smell, or touch of the substance, one may infer certain qualities. For example, a bitter, acrid taste may indicate heat; a sweet, slimy texture may suggest moisture. 2. **Reason and analogy** (*qiyās*): By comparing the drug’s known effects with those of other substances of known temperament. 3. **Experience** (*tajriba*): The most reliable method. When a drug is applied under controlled conditions and yields consistent results, its power is thereby confirmed. This is the method by which the early physicians determined the **degrees of strength** and specific **effects** of countless drugs. But one must be cautious: the same drug may act **differently** depending on the **temperament of the patient**, the **organ affected**, the **form in which the drug is administered**, and the **time of year**. Therefore, judgment must be based on **repeated observation** and **precise conditions**. **Chapter Three:** ### **On the Degrees of Potency** The **effect of a medicament** is not uniform in intensity. It varies by **degree**, and physicians classify these into **four degrees** (*darajāt arba**ʿ**ah*): 1. **First Degree**: Brings about a mild change; acts without harming natural temperament. 2. **Second Degree**: More pronounced effect; may alter temperament but not destroy function. 3. **Third Degree**: Strong effect; alters and may disturb function, approaching harm. 4. **Fourth Degree**: Extreme; either **destroys function** or causes a **radical change**—some poisons and potent purgatives fall in this category. Each degree is further described by **strength within the degree** (e.g., low second, high second). Accurate identification of the degree is essential to **avoid harm** and to **achieve therapeutic goals**. **Chapter Four:** ### **On the Actions of Simple Medicaments** Simple drugs may have **one or more of the following actions**, which are based on their quality and potency: - **Heating**: expands, thins, disperses. - **Cooling**: contracts, thickens, calms. - **Drying**: absorbs moisture, firms tissues. - **Moistening**: softens, dissolves dryness. They may also perform more **specific actions** such as: - **Astringent** (*qābi**ḍ*): contracts tissue and halts discharges. - **Laxative** (*mushil*): promotes evacuation of excess humors. - **Resolvent** (*muhallil*): dissolves swellings and hardenings. - **Attenuant** (*mula**ṭṭ**if*): thins thick substances. - **Incisive** (*qā**ṭ**i**ʿ*): breaks down thick, hard substances. Each action must be properly matched to: - The **nature of the disease**, - The **temperament of the patient**, - The **state of the affected organ**. Otherwise, the remedy may **worsen the illness** or create new problems. This completes **Discipline Two**: the general theory of **simple medicaments and their powers**.   **Discipline Three** ## **On Particular Diseases Affecting Individual Organs, One by One, From Head to Foot** (*fī al-amrā**ḍ**al-juz**ʾ**iyyah al-w**ā**qi**ʿ**ah bi-**ʿ**u**ḍ**w**ʿ**u**ḍ**w min al-insān min al-farq ilā al-qadam**ẓ**āhirihā wa-bā**ṭ**inihā*)   **Introduction to Discipline Three** In this section, I begin addressing the **specific diseases** (*amrā**ḍ**juz**ʾ**iyyah*) that affect the human body **organ by organ**, from the **top of the head** (*al-farq*) to the **soles of the feet** (*al-qadam*), covering both **external and internal** structures. The method adopted for each organ will typically follow this sequence: 1. **Anatomy** (*tashrī**ḥ*) of the organ: its form and structure. 2. **Function** (*manfa**ʿ**ah*): the role the organ plays in the body. 3. **Preservation** (*ḥ**if**ẓ**al-ṣi**ḥḥ**ah*): how to maintain its health. 4. **Diseases** (*amrā**ḍ*) that afflict it, in general terms. 5. **Causes** (*asbāb*) of those diseases. 6. **Signs** (*ʿ**alāmāt*) indicating disease or imbalance. 7. **General therapeutic principles** (*qawā**ʿ**id**ʿ**il**ā**jiyyah kulliyyah*) relevant to treatment. 8. **Particular treatments** (*ʿ**ilāj juz**ʾ**ī*): using appropriate **simple or compound remedies**. If the anatomy or function of an organ has already been discussed earlier—especially among the simple organs (*a**ʿ**ḍ**ā**ʾ**mufradah*)—it will not be repeated here except briefly. As for the **remedies** previously mentioned in the section on **simple medicaments**, or in the tables (*jadāwil*) and compound formulas (*aṣbāgh*) intended for specific illnesses, I will not repeat them here unless needed for clarity. If a treatment involves **compound medications** whose formulations are better suited for the **pharmacopoeia** (*al-Aqrabādhīn*), I will delay the explanation of their mixing and effects until that book. **Organization of the Section** Each chapter will address: - One or more **organs** (*a**ʿ**ḍ**ā**ʾ*), - The **particular conditions** associated with that organ, - How its diseases **manifest, evolve, and are managed**. As we move from the head downward, we follow both **a natural order** (from center of command to peripheries) and **a clinical logic**, since many systemic symptoms first appear in **localized disturbances**. In each case, I will emphasize the **principle of restoring balance** (*i**ʿ**ā**dat al-i**ʿ**tid**ā**l*) rather than mere suppression of symptoms. At this point, the treatise would begin with the **head**, focusing first on the **brain** and associated organs (eyes, ears, nose, etc.), then move progressively down the body. **Section One:** ### **On the Head and Its Organs** (*fī al-ra**ʾ**s wa-m**ā**ya**ḥ**tawī**ʿ**alayh*)   **Chapter One:** ### **On the Brain** (*al-dimāgh*)   1. #### **Anatomy and Function of the Brain** The **brain** (*al-dimāgh*) is one of the **principal organs** of the human body. It is located within the cavity of the skull (*ṭ**abaq al-jumjuma*), and is enclosed by membranes (*al-ṣafā**ʾ**if*) which serve to protect and support it. The brain is **cold and moist in temperament** by nature, and its substance is **soft and white**, particularly suited to its function. Its principal function is to serve as the seat of the **psychic faculty** (*al-quwwah al-nafsāniyyah*) and the **source of sensation and voluntary motion**. From it arise all the **nerves** (*al-**ʿ**aṣab*) which spread throughout the body, controlling movement, sensation, and mental operations such as thought, memory, imagination, and judgment. 1. #### **Preservation of Brain Health** To preserve the health of the brain: - Maintain **moderation of temperament**, avoiding excess cold, heat, dryness, or moisture. - Ensure proper regulation of **sleep and wakefulness**, since excess of either weakens the brain. - Avoid intense emotional disturbances like grief, fear, or anger, which directly impact psychic faculties. - Refrain from **strong smells** and **head-heavy foods** (such as onions, garlic, or fermented substances). - Use **gentle purgatives** to evacuate excess humors, especially phlegm, which tends to accumulate in the brain. - Favor **cooling and strengthening aromatics** like **rose**, **sandalwood**, **camphor**, and **vinegar vapors**. - Proper **ventilation** and **exposure to temperate air** are essential, as is regular **movement of the head and neck** without strain. 1. #### **General Brain Disorders** Brain diseases may arise from: - **Temperamental imbalances** (e.g., excessive heat, cold, moisture, or dryness), - **Obstruction** of vessels or nerves, - **Accumulation of harmful humors**, especially **phlegm** (*balgham*) and **black bile** (*sawdā**ʾ*), - **Physical trauma**, such as fractures or blows to the head. These diseases affect: - **Sensation**: leading to numbness, tingling, loss of smell, or vision. - **Motion**: leading to tremors, paralysis, or convulsions. - **Cognition**: leading to forgetfulness, madness (*junūn*), melancholia (*waswās*, *ḥ**uzn*), or confusion (*khub**ṭ*). 1. #### **General Therapeutic Principles** Treatment of brain disorders follows these steps: - **Correction of temperament**: apply heating or cooling, moistening or drying as needed. - **Evacuation of excess matter**: through purging (*ishāl*), cupping (*ḥ**ijāmah*), or nasal administration (*sa**ʿ**ū**ṭ*, *na**ṭ**ūr*). - **Strengthening of the organ**: through compound electuaries (*jawārish*), brain tonics (*muqawwī al-dimāgh*), and **fragrant oils** for anointment and inhalation. - Use of **light, well-digested foods** that do not produce excess phlegm. 1. #### **Example: Headache (Ṣudā****ʿ****)** **Types**: - Caused by **heat** → burning, pounding pain; worse in sun, better with cold. - Caused by **cold** → heaviness, dull ache; better with warmth. - Caused by **dryness** → tight, constricting pain. - Caused by **moisture** → sluggish, foggy sensation. - Caused by **wind** (*riyā**ḥ*) → moving pain, intermittent. - Caused by **vapors from stomach** → especially after eating or with indigestion. **Treatment**: - Determine the cause by temperament and symptoms. - Apply **corrective oils**, compresses, and vapors. - Administer **light purging** or vomiting if the cause is humoral. - Avoid bright light, noise, strong odors, and mental strain. This concludes the discussion on the **brain** and its general disorders.   **Chapter Two:** ### **On the Eyes** (*fī al-**ʿ**aynayn*) 1. #### **Anatomy and Function of the Eye** The **eye** (*ʿ**ayn*) is the **organ of vision** and among the most intricate and delicate of the sense organs. It is spherical in shape, composed of **several layers** and **humors** (*al-mawād*) of different consistencies—transparent, viscous, and fluid. Key parts include: - The **cornea** (*qarniyah*), the clear outer covering. - The **aqueous humor** (*rū**ḥ**al-mā**ʾ*), lying just beneath. - The **lens** (*ʿ**adasah*), the central body responsible for focusing. - The **vitreous humor** (*rū**ḥ**al-zujāj*), the gel-like substance filling the main cavity of the eye. - The **optic nerve** (*ʿ**aṣab al-baṣar*), which conveys the image to the brain. The eye is nourished and moistened by **lacrimal secretions** and surrounded by **protective structures**, such as the eyelids and eyebrows. 1. #### **Preservation of Eye Health** To preserve eyesight: - Avoid exposure to **intense light**, **smoke**, and **dust**. - Use **cooling and astringent eye washes** made from **rose water**, **saffron**, **camphor**, and **myrtle**. - Sleep sufficiently and avoid prolonged weeping or straining the eyes in darkness. - Strengthen the eye with **scented collyriums** (*ku**ḥ**l*) and protect it from **cold winds** or **head congestion**. - Abstain from consuming **thick, phlegmatic foods**, and from **overeating**, which can lead to congestion in the head and affect the optic nerve. 1. #### **General Eye Disorders** Eye diseases include: - **Inflammation** (*ramad*): redness, swelling, burning, often due to heat or vapors. - **Weakness of vision** (*ḍ**u**ʿ**f al-baṣar*): caused by overuse, old age, or dryness. - **Night blindness** (*ʿ**amā al-layl*): typically due to excess cold or liver dysfunction. - **Flow of tears** (*sīlān al-dumū**ʿ*): may result from irritation, obstruction, or excessive moisture. - **Opacity** (*kudrah*) or cataract (*al-mā**ʾ**al-n**ā**zil*): accumulation of thick humor in the lens or pupil. - **Itching, dryness, or heaviness**: symptoms of imbalance in temperament or humor. 1. #### **Treatment Principles** Treatment depends on diagnosis of cause: - For **heat-related inflammation**: cooling eye drops, rest, and mild purgation. - For **cold or moist causes**: warming and drying medications. - For **dryness**: moistening salves and strengthening collyriums. - For **cataract**: early cases may respond to specific collyriums; advanced stages may require surgical intervention. Topical applications are the primary method of treatment for eye disorders, including: - **Lotions** (*qarūra*), - **Powders** (*ghubār*), - **Collyriums** (*ku**ḥ**l*), - **Inhalants** (*shammūm*). Systemic treatments such as **diet adjustment**, **regimen**, and **humoral evacuation** are also employed to treat root causes. This concludes the discussion of the **eyes** and their disorders. **Chapter Three:** ### **On the Ears** (*fī al-udhunayn*) 1. #### **Anatomy and Function of the Ear** The **ear** (*udhun*) is the **organ of hearing** and is composed of three parts: 1. The **outer ear** (*al-**ẓ**āhirah*), including the auricle (*ṣinw*) and the auditory canal. 2. The **middle ear** (*al-wus**ṭ**ā*), which contains the **tympanic membrane** (*ghishā**ʾ**al-**ṭ**abl*) and a cavity filled with air. 3. The **inner ear** (*al-bā**ṭ**inah*), where the **auditory nerve** (*ʿ**aṣab al-sam**ʿ*) resides, extending to the brain and carrying the sound impressions. The ear is **dry and airy** in nature and requires openness and clarity to perceive sound properly. Sound is transmitted through **vibration and air movement**, ultimately reaching the brain via the auditory nerve. 1. #### **Preservation of Hearing** To maintain hearing and ear health: - Avoid **loud, sharp, or jarring sounds**. - Keep the ear canal **free of excess moisture** and **blockages**. - Refrain from inserting foreign objects into the ear. - Prevent exposure to **cold winds**, **dust**, or **smoke**. - Use ear drops prepared with **rose oil**, **musk**, or **saffron**, especially in the winter. - Treat **head congestion** promptly, as it may impair hearing through vapor accumulation near the ear. 1. #### **General Ear Disorders** Common diseases of the ear include: - **Pain** (*waja**ʿ**al-udhun*): due to heat, cold, or accumulated humors. - **Discharge** (*saylān*): often a result of **infection** or **ulceration**. - **Deafness** or **muffled hearing** (*ṣamm*): may stem from obstruction, dryness of the nerve, or corruption of the vital spirit. - **Tinnitus** (*tanīn*): perception of ringing or buzzing, linked to wind (*riyā**ḥ*) or vapor trapped in the canals. - **Itching or tingling**: often caused by irritants, dryness, or insects. 1. #### **Therapeutic Principles** Treatment follows the principle of **resolving the cause**: - **Heat**: cooling oils (like camphor or coriander oil). - **Cold**: warming drops (e.g., oil of rue or almond infused with musk). - **Moisture or discharge**: astringent and drying agents like rose oil or vinegar-based mixtures. - **Obstruction**: gentle cleaning and use of dissolving or evacuating oils. - **Tinnitus**: inhalants and fomentations to disperse vapor or wind. In some cases, general evacuative therapy (such as **head purging** via nasal insufflation) is needed in addition to **local treatment**.   **Chapter Four:** ### **On the Nose** (*fī al-anf*) 1. #### **Anatomy and Function of the Nose** The **nose** (*anf*) is the organ responsible for the sense of **smell** (*shamm*) and also plays a key role in **respiration** and the passage of **mucosal secretions**. It is composed of: - **External cartilage and bone**: which give it form and structure. - **Nasal passages** (*manākhir*): lined with membranes and fine hairs. - **Olfactory nerves** (*ʿ**aṣab al-shamm*): which extend from the upper part of the nasal cavity to the brain. The nose serves three main functions: 1. Detecting odors and vapors. 2. Warming and filtering inhaled air. 3. Assisting in voice resonance and speech modulation. Its **natural temperament** is **moderately moist**, suitable for trapping and processing inhaled substances.   1. #### **Preservation of Nasal Health** To preserve the health of the nose and sense of smell: - Keep the nasal passages **clear of excess phlegm** and **dry crusts**. - Avoid **cold, damp air** and exposure to **dust** or **irritants**. - Use **nasal washes** and **light oils** to maintain balance. - Inhale gentle, strengthening fragrances like **rose**, **basil**, **saffron**, or **amber**. - Avoid overuse of strong, acrid smells which fatigue the olfactory nerves. - Refrain from **drying habits**, like excessive fasting or exposure to extreme heat. 1. #### **Common Diseases of the Nose** Diseases include: - **Obstruction** (*insidād*): due to cold, swelling, or humoral accumulation. - **Loss or weakness of smell** (*faqd al-shamm* or *ḍ**u**ʿ**fuhu*): from cold temperament, head congestion, or nerve weakness. - **Irritation and itching**: due to dryness or allergic reactions. - **Epistaxis** (*ru**ʿ**ā**f* – nosebleeds): from heat, dryness, or rupture of fine vessels. - **Ulcers and sores** (*qurū**ḥ*): often caused by acrid vapors or infection. - **Polyp growths** (*ḥ**ami**ḍ*): soft or hard, arising from thick humors.   1. #### **Therapeutic Principles** Treatment depends on the nature of the condition: - For **cold-induced obstruction**: warming oils (e.g., oil of rue, almond, or thyme), fumigation, and nasal instillations (*na**ṭ**ūr*). - For **heat and inflammation**: cooling drops (rosewater, camphor), cold compresses. - For **loss of smell**: inhalation of stimulating substances like **musk**, **saffron**, **zarnab**, or **pepper vapors**; also general tonics for the brain. - For **nosebleeds**: apply cold compresses to the nape and nose, administer astringent snuffs like **vinegar**, **sumac**, or **myrtle oil**. - For **ulcers and polyps**: cleansing followed by drying and healing powders or ointments. In many cases, treatment of **head congestion** or humoral imbalance is a prerequisite for full recovery.   **Chapter Five:** ### **On the Mouth and Tongue** (*fī al-famm wa-l-lisān*) 1. #### **Anatomy and Function of the Mouth and Tongue** The **mouth** (*famm*) is the **entry point of nourishment** and the initial site of **digestion** and **speech production**. It consists of: - **Lips** (*shafatān*), - **Teeth** (*asnān*), - **Gums** (*lithah*), - **Palate** (*ḥ**anak*), - **Tongue** (*lisān*), - **Salivary secretions** and **mucosal lining**. The **tongue** is a **muscular organ**, soft and flexible, essential for: - **Articulation** of speech, - **Tasting** flavors via its sensory nerves, - Assisting in chewing, swallowing, and cleaning the mouth. Its temperament is **moist and slightly warm**, suited for perception of subtle tastes and fluid manipulation.   1. #### **Preservation of Oral and Lingual Health** To maintain the health of the mouth and tongue: - Clean the mouth regularly using **miswāk** (tooth-stick) or soft cleaning agents. - Rinse after meals with **rosewater**, **vinegar**, or **saltwater**. - Avoid **very hot**, **very cold**, or **spicy foods** that irritate the tissues. - Refrain from eating **excessively dry** or **sticky foods** that may collect between teeth. - Strengthen the tongue and palate with **aromatic powders** or **mild astringents** like **mastic**, **pomegranate rind**, or **sumac**.   1. #### **Diseases of the Mouth and Tongue** Diseases may affect: - **The lips**: swelling, cracking, ulcers due to heat, dryness, or infection. - **The tongue**: inflammation (*waram*), heaviness, numbness, tremor, ulcers, or discoloration. - **Taste perception**: may be lost or distorted due to nerve or temperamental disorders. - **The gums**: inflammation (*iltihāb*), bleeding, or retraction—often caused by heat or moisture. - **The palate**: pain, ulcers, dryness. - **The teeth**: pain (*waja**ʿ*), decay (*tasawwus*), or looseness.   1. #### **Therapeutic Principles** Treatment varies by cause and location: - For **hot inflammation**: cooling mouthwashes (rosewater with camphor, mulberry, or quince), topical cooling salves. - For **dryness and cracking**: moistening and healing ointments (almond oil, beeswax, cucumber juice). - For **ulcers**: cleansing, then application of healing agents like **honey**, **galls**, **pomegranate bark**, or **frankincense powder**. - For **tooth pain**: purging humors if systemic, local astringents (vinegar, clove oil), fumigation (*bukhhūr*), or extraction in extreme cases. - For **tongue tremors or heaviness**: treatment of **brain and nerve centers** as root causes, then application of tonics and balms. In all oral conditions, **systemic balance** must be addressed alongside **local therapy**. This includes adjusting diet, clearing humors, and supporting the **faculties** related to the tongue (especially **psychic** and **natural**).   **Chapter Six:** ### **On the Throat, Tonsils, and Related Structures** (*fī al-**ḥ**alq wa-l-lūz wa-mā yata**ʿ**allaq bihim**ā*)   1. #### **Anatomy and Function of the Throat and Tonsils** The **throat** (*ḥ**alq*) is the passage through which **air and food** travel, connecting the **mouth and nasal passages** to the **lungs** and **stomach**, respectively. It includes: - The **pharynx** (*jawf al-**ḥ**alq*), - The **larynx** (*ḥ**anjarah*), which produces voice, - The **epiglottis** (*la**ḥ**mīyah*), which prevents food from entering the trachea, - The **tonsils** (*lūz*), which are soft, gland-like tissues at the sides of the throat. These structures are essential for: - **Breathing** and **phonation**, - **Swallowing** safely, - **Defending** against harmful substances entering through the mouth or nose. The natural temperament of the throat is **warm and moist**, but it is easily disturbed by the environment, food, and vapors rising from the stomach.   1. #### **Preservation of Throat Health** To preserve the throat and tonsils: - Avoid **very hot or cold foods and drinks**, especially in quick succession. - Refrain from shouting, prolonged speaking, or inhaling smoke or dust. - Keep the neck and throat **warm**, especially in cold seasons. - Use **mild gargles** made from **rosewater**, **licorice**, or **mallow decoction**. - Strengthen the throat with **soothing lozenges** and **demulcents** (such as gum arabic or honey). - Prevent congestion in the head, as it often drains downward and affects the throat.   1. #### **Diseases of the Throat and Tonsils** Among the most common: - **Inflammation** (*waram*): redness, pain, difficulty swallowing or breathing. - **Swelling of the tonsils** (*intifākh al-lūz*): may obstruct the throat. - **Ulceration**: from acrid humors or infection. - **Hoarseness** or **loss of voice**: due to dryness, cold, or overuse. - **Coughing** and **irritation**: often from postnasal drip or ascending vapors. - **Foreign body sensation** (*ḥ**asakat fī al-**ḥ**alq*): sometimes imaginary, sometimes due to small ulcers or thick secretions.   1. #### **Therapeutic Principles** Treatment depends on the underlying cause and must be adjusted to the **patient’s temperament**, **age**, and **season**. - For **heat and redness**: gargles with **rosewater**, **vinegar**, and **mulberry**, or sucking on cold lozenges. - For **swelling**: topical cooling oils (e.g., **mallow**, **violet**) applied to the throat externally, and **cooling electuaries** taken orally. - For **dryness and hoarseness**: use moistening syrups such as **licorice**, **honey-water**, or **barley decoction**. - For **phlegmatic obstruction**: warming and thinning remedies—pepper water, vinegar gargle, thyme oil. - For **ulcers**: cleansing with mild gargles, followed by astringent and healing agents like **pomegranate rind**, **sumac**, or **frankincense powder**. Cupping (*ḥ**ijāmah*) behind the ears or at the nape may be used in severe inflammation. If the cause is **systemic**, such as **an excess of phlegm**, then **purgation** and regulation of the **digestive system** is essential in addition to local treatment.   Next in sequence is the **neck and nape**, or we may begin with the **chest and lungs**, moving downward as outlined.   **Chapter Seven:** ### **On the Chest and Lungs** (*fī al-ṣadr wa-l-ri**ʾ**ah*)   1. #### **Anatomy and Function of the Chest and Lungs** The **chest** (*ṣadr*) is the cavity that houses the **heart** and **lungs**, protected by the **ribs**, **sternum**, and **spinal column**. Its primary function is to **facilitate breathing** and **circulate the vital spirit** throughout the body. The **lungs** (*ri**ʾ**ah*) are spongy, porous organs situated on both sides of the heart. They are **cold and moist in temperament**, yet suited to receiving and moderating the **heat** of the heart. The lungs’ main functions are: - Drawing in **air** (*tanuffus*) and expelling it (*zafīr*), - Cooling the **vital spirit** produced in the heart, - Assisting the **voice** and **speech production**, - Acting as filters for vapors and airborne impurities.   1. #### **Preservation of Chest and Lung Health** To maintain the health of the chest and lungs: - Avoid **dust**, **smoke**, **dense vapors**, and polluted air. - Stay away from **overexertion**, especially in dry, hot air. - Use **mild expectorants** (like honey and licorice) to cleanse the lungs. - Strengthen the lungs with inhalants such as **rose**, **myrtle**, **sandalwood**, and **camphor**. - Regulate the **intake of food** and **emotion**, since both affect breathing and chest constriction. - Promote gentle **exercise** that opens the chest without inducing exhaustion.   1. #### **Diseases of the Chest and Lungs** Diseases may arise from: - **Temperamental imbalance** (e.g., excess dryness, cold, or heat), - **Obstruction** by thick humors or phlegm, - **Weakness** of the lung’s faculty (*quwwah*), - **Inflammation** or **ulceration** of the airways. Common disorders include: - **Cough** (*su**ʿ**ā**l*): may be dry or productive, due to irritation, phlegm, or heat. - **Shortness of breath** (*ḍ**īq al-nafas*): from obstruction, vapor, or weakness. - **Asthma-like constriction** (*rabw*): often related to accumulated moisture or thick phlegm. - **Pleurisy** (*dhāt al-janb*): sharp pain at the sides, often with fever and difficulty breathing. - **Hemoptysis** (coughing blood): often from vessel rupture due to excessive heat, dryness, or strain. - **Weak voice or hoarseness**: usually a result of dryness, phlegm, or vocal fatigue.   1. #### **Therapeutic Principles** Treatment is directed at: - **Balancing the temperament** of the lungs (cooling, moistening, or drying), - **Expelling harmful matter**, especially excess phlegm or bile, - **Soothing and strengthening** the lung tissue. Remedies include: - **Liquids and syrups**: made from **licorice**, **fig**, **raisins**, **barley water**, and **violet syrup**. - **Lozenges and electuaries**: made with **honey**, **mastic**, **saffron**, or **sugar-based pastes**. - **Steam inhalation**: using warm decoctions of **thyme**, **mallow**, **eucalyptus**, or **fenugreek**. - **Dry cupping** on the chest or upper back. - **Purgation** of excess humors from the head and chest via nasal treatments or light laxatives. Diet should be **light**, **moistening**, and **non-irritating**—with avoidance of salted, sour, or overly spicy foods.   **Chapter Eight:** ### **On the Heart and Its Disorders** (*fī al-qalb wa-amrā**ḍ**ihi*)   1. #### **Anatomy and Function of the Heart** The **heart** (*qalb*) is the **chief vital organ** (*ʿ**u**ḍ**w al-ra**ʾ**ī**s**ī**al-**ḥ**ayawānī*), located in the **left side of the chest**, protected by the sternum and ribs, and embraced by the lungs on either side. Its temperament is **naturally hot and dry**, suited to the generation and distribution of the **vital spirit** (*al-rū**ḥ**al-**ḥ**ayawānī*). Its principal functions are: - Generating **innate heat** necessary for life, - Distributing **vital spirit** through the arteries, - Serving as the center of **life, vigor, and courage**, - Reacting sensitively to **emotions**, especially joy and sorrow. The heart communicates with the **lungs**, **brain**, and **liver**, forming the triad of life-sustaining organs. Any significant disturbance in its heat, structure, or rhythm can endanger life rapidly.   1. #### **Preservation of Heart Health** To preserve heart health: - Avoid **sudden emotional shocks** (excessive fear, grief, or joy), as they directly affect the heart’s rhythm and spirit. - Maintain a **balanced temperament**, avoiding excessive **heat**, **thirst**, or **mental strain**. - Strengthen the heart with **scented tonics** (like saffron, rose, camphor, sandalwood, musk). - Avoid **overexertion**, especially in heat or strong sun. - Use **light, easily digestible food** that does not produce congestion or excessive vapors. - Keep **blood pure and flowing** by occasional light cupping or gentle purging.   1. #### **Diseases of the Heart** Heart diseases may be: - Structural (*ṣinfī*) — such as congenital defects or trauma; - Functional (*fi**ʿ**l**ī*) — such as irregular motion, weakness of heat, or failure of vital spirit; - Emotional (*nafsānī*) — such as those resulting from sadness, fear, or excessive delight. Notable disorders include: - **Palpitations** (*khafaqān*): rapid, irregular heartbeat often from vapor, obstruction, or emotional turmoil. - **Fainting** (*ighmā**ʾ*): collapse of consciousness due to weakness in the heart’s heat or spirit. - **Cardiac pain** (*waja**ʿ**al-qalb*): sharp or constricting pain, often from accumulated bile or cold vapor. - **Heart weakness** (*ḍ**u**ʿ**f al-qalb*): general fatigue, loss of stamina, or coldness in the chest. - **Excessive heat**: may produce thirst, restlessness, dry mouth, and insomnia. - **Emotional afflictions** (*marā**ḍ**nafsānī*): melancholy, fear, or passion that disturb the heart’s balance.   1. #### **Therapeutic Principles** Treatments aim to: - **Balance the heart’s heat**, - **Strengthen the vital spirit**, - **Resolve underlying humoral excesses**, especially of black bile or yellow bile, - **Calm emotional turmoil**. Recommended therapies: - **Cooling and calming syrups**: such as **rose syrup**, **violet**, or **lemon balm decoction**. - **Tonics for the heart** (*muqawwī al-qalb*): saffron, spikenard, cinnamon, mastic, or pearls (if available). - **Scented preparations**: worn on the chest or inhaled—rose oil, sandalwood paste, camphor, or ambergris. - **Avoidance of pungent spices**, excessive wine, or heavy meats. - **Management of emotions**: through counsel, tranquility, soft music, or gentle environment. In some cases, **bloodletting** or **cupping** may be used to relieve tension, especially in strong individuals with excess blood.   **Chapter Nine:** ### **On the Liver and Its Disorders** (*fī al-kabid wa-amrā**ḍ**ihā*)   1. #### **Anatomy and Function of the Liver** The **liver** (*kabid*) is the **principal organ of nutrition** and the **seat of the natural faculty** (*al-quwwah al-**ṭ**abī**ʿ**iyyah*). It is located in the **right upper quadrant** of the abdomen, beneath the diaphragm, and partially protected by the ribs. Its **natural temperament** is **warm and moist**, suited to its role in transforming food into blood and generating the four humors (*akhlā**ṭ*). The liver’s primary functions are: - Receiving **chylous matter** (partially digested food) from the stomach, - Transforming it into **blood** and **humors** via **natural heat**, - Distributing nourishment throughout the body via the **veins**, - Supporting **growth**, **reproduction**, and **repair** of tissues. It is also indirectly involved in the **regulation of temperament**, the health of the **skin**, and the **clarity of the eyes**.   1. #### **Preservation of Liver Health** To maintain liver health: - Avoid **overindulgence** in food, drink, or alcohol. - Prevent **anger**, **rage**, or excessive emotional heat, which disturbs hepatic function. - Favor **moistening, cooling foods**: barley water, lettuce, cucumber, endive. - Refrain from **frequent hunger** or **dry diets** that damage the liver's moisture. - Use **mild laxatives** to relieve bile accumulation, such as tamarind or prunes. - Avoid exposure to **extreme heat**, especially during digestion. Tonics such as **rose syrup**, **pomegranate**, **rhubarb**, and **sandalwood decoction** may be used seasonally to strengthen the liver.   1. #### **Diseases of the Liver** Liver diseases may arise from: - **Humoral imbalance**, particularly excess **yellow bile** (*ṣafrā**ʾ*) or **black bile** (*sawdā**ʾ*), - **Blockage** of vessels or ducts, - **Weakness of faculty**, - **Inflammation** or **hardening** of tissue. Common disorders include: - **Hepatic inflammation** (*waram al-kabid*): often accompanied by fever, pain, thirst, and dry skin. - **Enlargement of the liver** (*takhm al-kabid*): from congestion or retention of thick humors. - **Hardening (cirrhosis-like)** (*taṣallub*): due to chronic dryness or black bile dominance. - **Jaundice** (*yaraqān*): yellowing of skin and eyes, caused by obstruction of bile flow. - **Dropsy (ascites)** (*istisqā**ʾ*): fluid retention due to liver failure. - **Loss of appetite**, **digestive heaviness**, and **melancholy**: often traced to hepatic dysfunction.   1. #### **Therapeutic Principles** Treatment must match the **temperament** and **cause** of the disease: - For **heat and inflammation**: cooling, moistening agents (e.g., chicory, endive, barley, rose). - For **excess yellow bile**: use purgatives like **tamarind**, **cucumber seed**, or **violet syrup**. - For **blockage or swelling**: administer decoctions with **mollifying** and **resolving** herbs (e.g., mallow, flax, chamomile). - For **hardness**: oils and poultices to soften tissue, such as **lily root**, **mallow oil**, or **fatty ointments**. - For **weakness**: use hepatic tonics like **rose**, **saffron**, **mastic**, and **cinnamon**. - For **jaundice**: purgatives, diuretics, and bitter agents (e.g., **caper root**, **celery**, **chicory syrup**). - For **dropsy**: regulation of **fluid intake**, **drying diet**, diuretic drugs, and evacuation of thick humors. As always, attention to **diet**, **digestion**, and **general temperament** is central to the treatment plan.   **Chapter Ten:** ### **On the Stomach and Its Disorders** (*fī al-mi**ʿ**da wa-amr**ā**ḍ**ihā*)   1. #### **Anatomy and Function of the Stomach** The **stomach** (*mi**ʿ**da*) is the primary organ of **digestion** (*hadhm*), located in the upper abdomen, just beneath the diaphragm and slightly to the left of the liver. It is a **muscular, hollow organ**, with a naturally **warm and moist temperament**, ideally suited to its task of receiving food and preparing it for transformation by the liver. Its functions include: - **Receiving food** from the esophagus, - **Digesting it** through natural heat and moisture, - **Passing the chyle** (partially digested food) through the **pylorus** to the liver, - **Expelling waste gases** upward (belching) or downward (flatulence), - Influencing the entire **digestive system**, and indirectly the **brain** and **heart**, due to vapor transmission. The stomach is highly sensitive to **diet**, **emotions**, and **environmental factors**. 1. #### **Preservation of Stomach Health** To preserve the stomach’s health: - Eat at **regular intervals**, allowing prior meals to digest fully. - Avoid **overeating** or **fasting for too long**, both of which harm the stomach's faculty. - Chew food thoroughly; avoid swallowing large pieces. - Choose foods that are **light**, **moist**, and **easy to digest**—like chicken, lentils, barley, and cooked fruits. - Avoid **cold water immediately after eating**, as it weakens natural heat. - Refrain from **sudden emotional shocks** (e.g., anger or fear) while eating. - Use gentle **aromatic tonics** (e.g., fennel, mint, thyme) to maintain digestive vigor.   1. #### **Diseases of the Stomach** Diseases may affect: - The **digestive power** (*quwwat al-hadhm*), - The **structure** (e.g., ulcers, swellings), - The **motions** (e.g., delayed emptying, spasms), - The **vapor** it produces, which may rise and affect other organs. Common disorders include: - **Indigestion** (*sū**ʾ**al-hadhm*): heaviness, bloating, belching, or nausea. - **Weak digestion**: due to cold, dryness, or phlegm. - **Gastric inflammation** (*waram al-mi**ʿ**da*): pain, heat, thirst, vomiting. - **Acidity** and **sour belching**: from excess bile or spoiled food. - **Appetite disorders**: excessive hunger (*nuhūm*) or lack of appetite (*qillat al-shahwah*). - **Flatulence** (*riyā**ḥ*): due to weak digestion and vapor accumulation. - **Nausea and vomiting** (*ghathayān wa-qay**ʾ*): may arise from excess matter, obstruction, or nervous stimulation. - **Hiccups** (*sha**ḥ**īq*): result of diaphragmatic disturbance or gastric irritation.   1. #### **Therapeutic Principles** Treatment is tailored to the **nature of the disturbance** and the **temperament of the patient**: - For **weak digestion**: warming and strengthening tonics such as **fennel**, **thyme**, **cumin**, **anise**, or **ginger**. - For **inflammation**: cooling, moistening remedies like **barley water**, **mallow**, **cucumber juice**, **violet**, and **rose syrup**. - For **acid reflux** and **bile excess**: use **mild purgatives** (e.g., tamarind), cooling electuaries (e.g., lemon balm), and avoid spicy or oily food. - For **phlegmatic bloating**: warming and drying agents such as **pepper**, **cinnamon**, and **rue**. - For **flatulence**: administer **carminative pills** or decoctions of **caraway**, **bay leaves**, and **nutmeg**. - For **loss of appetite**: aromatics, gentle bitters (e.g., celery seed, bitter orange), and pre-meal tonics. - For **hiccups**: treat underlying gastric irritation or emotional cause; apply warm compresses to the epigastric area. In all cases, the **diet is central**. Avoid what the stomach cannot digest. Meals should be light, warm, and suited to one’s age, season, and activity.   **Chapter Eleven:** ### **On the Intestines and Bowel Disorders** (*fī al-am**ʿ**ā**ʾ**wa-l-mu**ʿ**idah wa-amr**ā**ḍ**ihā*)   1. #### **Anatomy and Function of the Intestines** The **intestines** (*al-am**ʿ**ā**ʾ*) are the tubular structures that extend from the **pylorus** of the stomach to the **anus**. They are divided into: 1. **Small intestines** (*al-am**ʿ**ā**ʾ**al-ṣighār*): where further digestion and absorption of nutrients occurs. 2. **Large intestines** (*al-am**ʿ**ā**ʾ**al-kib**ā**r*): where remaining moisture is absorbed and fecal matter is formed and transported. The **natural temperament** of the intestines is **moderately warm and moist**, necessary for **peristalsis** (movement), digestion, and evacuation. They are also influenced by the liver (through the **bile**) and by the **stomach** and **nerves** that govern motion and sensation.   1. #### **Preservation of Intestinal Health** To maintain healthy intestines: - Maintain a **regular schedule** of eating and evacuating. - Avoid **constipation** and **retention** of stool, as this causes accumulation of harmful vapors. - Refrain from excessive purging or the use of strong **purgatives** unless medically necessary. - Favor **soft, moist, easily digestible foods** that aid regular bowel function—like cooked vegetables, figs, prunes, and barley soup. - Avoid foods that are **too dry**, **salty**, or **spicy**, which irritate the bowels. - Use **light oils** or **emollients** when signs of dryness or intestinal fatigue appear. - Be cautious in cold seasons, as cold suppresses intestinal motion and hardens stool.   1. #### **Common Intestinal Disorders** Disorders may involve: - **Motion**: constipation (*qab**ḍ*), diarrhea (*ishāl*), irregularity, or spasms. - **Structure**: swelling, herniation, or obstruction. - **Content**: presence of harmful humors or parasites. - **Sensation**: pain, cramping, or tenesmus (feeling of incomplete evacuation). Typical diseases include: - **Constipation**: from dryness, weak peristalsis, or blockage. - **Diarrhea**: from bile, undigested food, spoiled substances, or irritation. - **Colic** (*qawlunj*): severe cramping pain due to trapped wind or thick humors. - **Worm infestation** (*dūd*): common in children, producing itching, restlessness, and digestive weakness. - **Dysentery** (*z**ḥ**īr*): inflammation with bloody or mucous stools—often due to corrupted bile or ulceration. - **Prolapse of rectum** (*squū**ṭ**al-mu**ʿ**idah*): due to strain, weakness, or dryness.   1. #### **Therapeutic Principles** Treatment depends on correcting **temperament**, **clearing excess matter**, and **supporting intestinal motion**. - For **constipation**: moistening foods (cooked fruits, olive oil), and gentle laxatives (senna, prunes, tamarind, chicory). - For **diarrhea**: - If from excess bile: cooling and astringent agents (e.g., pomegranate peel, plantain, quince). - If from cold: warming agents (ginger, cinnamon). - For **colic**: - Disperse wind with **carminatives** (fennel, anise, cumin), - Apply warm compresses to the abdomen, - Use enemas (*ḥ**uqan*) with oil, milk, or decoctions. - For **worms**: administer specific **vermifuge** agents (e.g., pomegranate bark, aloe, myrobalan), and avoid sweet, heavy foods that nourish parasites. - For **dysentery**: treat with **cooling astringents**, mucilaginous decoctions (e.g., marshmallow, mallow), and mild purging of bile if needed. - For **prolapse**: strengthen rectal muscles, apply **astringents** externally (e.g., galls, alum), and reduce strain with diet and laxatives. Throughout treatment, **dietary discipline**, **emotional calm**, and **posture** (e.g., avoiding straining during defecation) are essential.     **Chapter Twelve:** ### **On the Kidneys and Bladder** (*fī al-kulyatayn wa-l-mathānah*)   1. #### **Anatomy and Function of the Kidneys and Bladder** The **kidneys** (*kulyatān*) are two **bean-shaped organs** located at the back of the abdominal cavity on either side of the spine. Their **temperament** is naturally **cold and moist**, though they require a degree of internal heat to perform their function efficiently. The **bladder** (*mathānah*) lies lower in the abdomen and serves as a **receptacle** for urine until its expulsion. ##### **Functions of the kidneys**: - Filter **excess moisture** and **waste** from the blood, especially from digested food, - Produce **urine**, which flows down to the bladder via the **ureters**. ##### **Functions of the bladder**: - Receive, store, and expel urine through the **urethra** during micturition. The health of both organs is dependent on: - The **heat and strength** of the kidneys, - The **openness and smoothness** of the urinary pathways, - The **consistency and clarity** of the humors in the blood.   1. #### **Preservation of Urinary Organ Health** To preserve the health of kidneys and bladder: - Drink **adequate fluid**, particularly **warm, easily absorbable liquids** like barley water or fennel decoction. - Avoid **overly salty**, **dry**, or **spicy foods**, which burden the kidneys and bladder. - Prevent exposure to **cold**, especially of the lower back and loins. - Avoid **retaining urine** unnecessarily, as it leads to bladder weakness. - Strengthen the kidneys with **tonic preparations** (e.g., asparagus, celery seed, galingale, and honey-based electuaries). - Maintain gentle regular activity to aid **circulation and drainage** of waste.   1. #### **Common Diseases of the Kidneys and Bladder** Typical disorders include: - **Back pain** (*waja**ʿ**al-kul**ā*): may result from inflammation, strain, or accumulation of waste. - **Difficulty in urination** (*ʿ**usrat al-bawl*): from obstruction, weakness, or dryness of the bladder or urethra. - **Frequent urination** (*kathrat al-bawl*): due to cold temperament, thin urine, or irritants. - **Burning urination**: often caused by bile or heat in the urinary tract. - **Urinary retention** (*ḥ**abs al-bawl*): from blockage, nervous dysfunction, or thickened humors. - **Stone formation** (*ḥ**aṣā**ʾ*): resulting from sedimentation of thick, viscous humors. - **Blood in urine** (*dam fī al-bawl*): may be from rupture, ulcers, or excessive heat in the kidneys or bladder. - **Incontinence** (*salas al-bawl*): due to sphincter weakness or nerve dysfunction.   1. #### **Therapeutic Principles** Therapy is tailored to the specific disturbance and its cause: - For **burning urine** or **heat**: use cooling, mucilaginous drinks (e.g., **barley water**, **cucumber juice**, **mallow**, **licorice**). - For **urinary retention**: - If from cold: warming agents like **fennel**, **anise**, **cinnamon**. - If from obstruction: lubricating enemas (*ḥ**uqan*) and **diuretics** (e.g., parsley seed, celery). - For **stones**: administer **stone-breaking agents** (*mufattit*), such as **caper root**, **mallow root**, **chicory**, and **mallow oil**, often combined with **milk** or **honey**. - For **back pain of renal origin**: fomentations with warming oils, rest, gentle massage, and avoidance of heavy lifting. - For **incontinence**: astringent tonics (e.g., **galls**, **myrtle**, **rose**), pelvic exercises, and avoiding cold exposure. Diet should be **light**, low in **salt** and **acrid substances**, and include foods that **promote urine flow** without irritating the tract.   **Chapter Thirteen:** ### **On the Reproductive Organs (Male and Female)** (*fī al-**ʿ**a**ḍ**w al-nāsil wa-l-ra**ḥ**im wa-amrā**ḍ**ihimā*)   1. #### **Anatomy and Function of the Reproductive Organs** ##### **For Men:** The **male reproductive organ** (*al-**ʿ**a**ḍ**w al-nāsil*) includes: - The **penis** (*dhakar*), - The **testicles** (*khusayatān*), - The **seminal ducts** (*masālik al-manī*). The organ’s natural temperament is **warm and moist**, suitable for generating and expelling **semen** (*manī*), which is derived from the finest nutritional residues processed by the liver and further refined in the testicles. Functions: - Expulsion of **urine** and **semen**, - Role in **procreation** and **sexual function**, - In some views, contributing to **psychic equilibrium** when discharge is regulated and temperate.   ##### **For Women:** The **female reproductive system** includes: - The **womb** (*ra**ḥ**im*), - The **vagina** (*farj*), - The **ovaries and tubes** (*not always anatomically distinct in classical texts*). The **womb** is a **muscular, hollow organ** situated in the lower abdomen. Its natural temperament is **cool and moist**, yet it is affected by many internal and external factors—especially the movement and retention of **blood**. Functions: - Reception of semen, - Nourishment of the embryo, - Expulsion of the fetus during birth, - Regular discharge of **menses** (*ḥ**ay**ḍ*) to cleanse excess blood.   1. #### **Preservation of Reproductive Health** ##### **For Men:** - Avoid **excessive sexual activity**, which weakens the back, brain, and heart. - Refrain from prolonged **retention of semen**, which may cause melancholy or heaviness. - Strengthen with tonics (e.g., **asparagus**, **rocket seed**, **nutmeg**, **amber**). - Prevent exposure of the loins to **cold** or **damp**. - Avoid heavy or cold-inducing foods that suppress desire or thicken semen. ##### **For Women:** - Regulate **menses** through warmth, light activity, and proper diet. - Avoid **sudden cold**, especially to the lower abdomen. - Use **emollients**, **sitz baths**, and **warming oils** to preserve womb suppleness. - Refrain from excessive fasting or violent emotions that disrupt the womb’s order.   1. #### **Common Disorders** ##### **In Men:** - **Impotence** (*ʿ**ajz*): from cold temperament, exhaustion, or obstruction in semen channels. - **Premature ejaculation** (*sura**ʿ**at al-inz**ā**l*): often from weakness of restraint or heat. - **Seminal emission during sleep** (*i**ḥ**tilām*): common in youth, problematic if excessive. - **Swelling or pain in testicles** (*waram*): from trauma, cold, or congestion. - **Hernias** (*inqilāb*): displacement of bowels into the scrotum due to weakness. ##### **In Women:** - **Suppression of menses** (*ḥ**abs al-**ḥ**ay**ḍ*): due to cold, fear, or blockage. - **Excessive menstruation** (*kathrat al-**ḥ**ay**ḍ*): from heat or blood surplus. - **Womb pain** (*waja**ʿ**al-ra**ḥ**im*): from swelling, dryness, or cold vapor. - **Uterine prolapse** (*squū**ṭ**al-ra**ḥ**im*): often from childbirth trauma or weakness. - **Sterility** (*ʿ**uqm*): due to dryness, obstruction, poor semen retention, or systemic weakness.   1. #### **Therapeutic Principles** - For **impotence**: warming, strengthening agents like **clove**, **mace**, **ginger**, **saffron**; warming electuaries and topical oils. - For **semen quality**: regulate diet, use semen-forming foods (e.g., **egg yolk**, **almonds**, **milk**, **dates**). - For **swelling or pain**: topical cooling or resolving oils (e.g., **mallow**, **vinegar**, **rose oil**). - For **blocked menses**: fomentation, sitz baths, and agents like **black seed**, **fennel**, **rue**, or **cinnamon**. - For **excess bleeding**: cooling, astringent remedies (e.g., **galls**, **myrtle**, **pomegranate rind**, **plantain**). - For **womb weakness**: strengthen with **rose oil**, **mastic**, **nutmeg**, and supportive girding. - For **sterility**: assess both partners; balance humors, regulate temperament, and use womb-cleansing treatments. **Chapter Fourteen:** ### **On the Joints, Limbs, and Musculoskeletal System** (*fī al-mafāṣil wa-l-a**ʿ**ḍ**ā**ʾ**al-**ḥ**arakiyyah*)   1. #### **Anatomy and Function** The **musculoskeletal system** consists of: - **Bones** (*ʿ**i**ẓ**ām*): rigid structures providing **support** and **framework**. - **Joints** (*mafāṣil*): connections between bones allowing **motion** and **flexibility**. - **Muscles** (*ʿ**a**ḍ**alāt*): soft tissues enabling **movement** by contraction and relaxation. - **Tendons** (*ʿ**uṣb* or *rawābi**ṭ*): cords connecting muscles to bones. - **Ligaments** (*arba**ṭ**ah*): connective tissues stabilizing joints. - **Cartilage** (*ghu**ḍ**rūf*): smooth tissue cushioning joints and allowing motion without friction. Their collective purpose is to: - Support **posture**, - Enable **voluntary movement**, - Maintain **balance and locomotion**, - Protect internal organs (e.g., ribs around heart and lungs). Temperament: Bones tend toward **dry and cold**, joints require **lubrication**, and muscles are **warm and moist**, favoring active motion.   1. #### **Preservation of Musculoskeletal Health** - Maintain **moderate physical activity** to preserve tone and circulation. - Avoid **excessive strain** or heavy lifting, especially in old age or illness. - Ensure **regular stretching**, especially of major joints (shoulders, hips, knees). - Use **rubbing** (*dalak*) with warming oils (e.g., **olive**, **mastic**, **laurel**) to preserve flexibility and prevent stiffness. - Avoid **cold drafts**, especially during sleep or after bathing. - Provide sufficient **nutrition** rich in **calcium-like** components (e.g., milk, sesame, bone marrow). - Use **baths and steam** for softening stiff limbs in older individuals.   1. #### **Common Ailments** - **Joint pain** (*waja**ʿ**al-maf**ā**ṣil*): from cold, dryness, or swelling of humors. - **Stiffness** (*taṣallub*): often due to cold and dryness, especially in the elderly. - **Dislocation** (*khal**ʿ*): when joint bones slip from their proper position. - **Fractures** (*kasr*): due to trauma; healing depends on strength of bones and patient’s constitution. - **Muscle wasting** (*dhu**ʿ**f al-**ʿ**a**ḍ**alāt*): due to inactivity, cold, or nerve weakness. - **Swelling of joints** (*waram*): can be hot (inflammatory), cold (humoral accumulation), or hard (thick residue). - **Gout** (*naqras*): from excessive thick, viscous humors (especially from meats, wines, or rich foods), affecting feet and toes. - **Sciatica** (*ʿ**irq al-nasā**ʾ*): pain along the hip and leg, caused by cold humors or obstruction along the nerve tract.   1. #### **Therapeutic Principles** - For **pain and stiffness**: warming oils (e.g., **mustard**, **cinnamon**, **clove**) and fomentations; dry cupping (*ḥ**ijāmah*) where appropriate. - For **dislocations and fractures**: reduction (manual adjustment), splinting (*taṣfī**ḥ*), immobilization, and bone-healing plasters (e.g., **dragon’s blood**, **pine resin**, **egg shell ash**). - For **muscle weakness**: tonic foods (e.g., **lamb**, **dates**, **wheat**), daily **massage**, and graduated activity. - For **swelling**: - If hot: **cooling compresses**, leech therapy, and gentle drainage. - If cold: warming plasters and stimulating liniments. - For **gout**: dietary control (avoid red meats, lentils, wine), use of **stone-dissolving agents**, **alkaline drinks**, and purgatives (e.g., **cucumber seed**, **cassia**, **mallow**). - For **sciatica**: intense warming therapy, fumigations, cupping along the nerve tract, and use of **ass’s milk**, **bitter almond oil**, and **wild celery**.   **Chapter Fifteen:** ### **On the Skin, Hair, and Matters of Adornment** (*fī al-jild wa-l-sha**ʿ**r wa-l-z**ī**nah*)   1. #### **The Skin and Its Functions** The **skin** (*al-jild*) is the outermost covering of the human body. It serves as: - A **protective barrier** from heat, cold, moisture, and dryness, - A **regulator of temperament** (by facilitating sweating or insulation), - A **sensorial surface** for touch, pain, and temperature, - An **indicator of internal health**, especially humoral imbalances. Its natural temperament is **moderately warm and moist**, though it varies by location (e.g., palms drier, scalp more oily).   1. #### **Hair and Its Qualities** ##### **Hair** (*sha**ʿ**r*) grows from pores in the skin. Its character depends on: - The **strength of the pores**, - The **quality of humors feeding it**, - The **temperament** of the skin and the body. Qualities: - **Thick hair**: denotes abundance of blood and warmth, - **Thin or sparse hair**: may indicate weakness, dryness, or cold humors, - **Curly hair**: from dryness and heat, - **Straight hair**: from moist and cool temperaments. Growth is faster in **youth**, slower in **old age**. Hair may fall from **illness**, **shock**, **excess heat**, or **nutritional deficiency**.   1. **Preservation and Beautification of the Skin and Hair** ##### **For the Skin:** - Bathe with **lukewarm water** and **cleansing agents** (e.g., **sīd**, **ḥ****imṣ powder**, or **wheat bran**). - Use **moisturizers** after washing (e.g., **rose water**, **violet oil**, **lily oil**) to prevent dryness. - Avoid strong sunlight and cold winds without protection. - Rub with **soft cloth** to maintain circulation. **For the Hair:** - Oil regularly with **olive**, **almond**, **castor**, or **myrtle oil** (*zayt al-ās*). - Wash with **soothing agents** (e.g., **sidr**, **lotus**, or **barley water**). - Trim split ends to encourage growth. - For hair loss, use **tonics** like: - Paste of **onion juice** and **honey**, - Infusion of **fenugreek** and **cress**, - Rubbing scalp with **garlic oil**, **black seed**, or **camphor oil**.   1. #### **Adornment and the Discipline of Zīnah** **Zīnah** (Adornment) in the medical tradition is not vanity, but the **preservation of harmony** and **beauty in appearance** as a reflection of internal health. It includes: - **Clarity and color of skin**, - **Freshness of complexion**, - **Strength and neatness of hair, nails, and teeth**, - **Body odor control**, - **Symmetry of body shape**. **Medical Recommendations for Zīnah:** - Diets that favor balance: moderate meats, fruits, lentils, and cooling drinks. - Avoid excessive sweating, constipation, or sleep deprivation, which darken complexion. - Use **natural perfumes** (e.g., **musk**, **amber**, **sandalwood**) to please the senses. - Keep nails trimmed and smooth; brush teeth with **miswāk**, **walnut bark**, or **pomegranate root**. - Apply **rouge**, **kohl**, and **henna** for cosmetic purposes—but with attention to moderation and naturalness.   **Chapter Sixteen:** ### **On General (Non-Localized) Diseases** (*fī al-amrā**ḍ**allatī idhā waqa**ʿ**at lam takhtaṣṣ bi-**ʿ**u**ḍ**win bi-**ʿ**aynihi*)   These are diseases that affect the **entire body**, or arise from systemic imbalances in **humors**, **temperaments**, or **vital forces**—rather than from a single organ. The physician must approach such conditions with greater attention to **overall constitution**, **environmental causes**, and **dietary habits**.   1. #### **Fevers (Al-****Ḥ****ummayāt)** A **fever** (*ḥ**ummá*) is the result of **heat** generated inside the body due to **blocked humors**, **putrefaction**, or **external invasion**. It may be: - **Ephemeral** (*ḥ**ummá nāshi**ʾ**ah*): caused by transient environmental or dietary factors. - **Humoral** (*ḥ**ummá damawiyyah*, *ṣafrāwiyyah*, *sawdāwiyyah*, *balghamiyyah*): each caused by overheating or imbalance of **blood**, **yellow bile**, **black bile**, or **phlegm**, respectively. - **Tertian, quartan, daily**: determined by cycles of attack and remission. **Signs**: shivering, flushing, dry mouth, rapid pulse, restlessness. **Treatment**: - **Humoral purification** (*istifrāgh*): via bloodletting, vomiting, or purgation. - **Cooling agents**: barley water, chicory, endive (*hindibā**ʾ*), coriander. - **Light diet**: gruels, barley soup, avoiding meat, fats, and wine. - **Sleep and rest**: critical to restore vital energy.   1. #### **Toxins and Poisons (Al-Sumūm)** Toxins may enter via: - Ingestion (spoiled food, toxic herbs), - Inhalation (foul air, noxious vapors), - Skin (snakebite, scorpion sting). **Signs**: sudden pain, color change, vomiting, delirium, collapse. ##### **Antidotes** (*tiryaq*): - **Thēriaque** (*tiryāq*): a compound of multiple ingredients, including opium, cinnamon, myrrh, and honey. - **Simple remedies**: rue (*fījil*), vinegar, pomegranate peel, purslane (*baqla**ḥ**amqā**ʾ*), activated charcoal. - **Emergency methods**: cupping near site, cold compresses, emetics.   1. #### **Wasting Conditions and Emaciation (Al-Dhubl wa-l-Nu****ḥ****ūl)** **Emaciation** may stem from: - Poor digestion, - Excess heat drying humors, - Nervous conditions (grief, insomnia), - Chronic illness or excessive physical exertion. **Remedies**: - Strengthening foods: **bone marrow**, **dates**, **wheat porridge**, **egg yolk**. - Light meats: **young chicken**, **rabbit**, **quail**. - Tonics: **rose syrup**, **pear juice**, **licorice**. - Emotional care: pleasant conversation, fragrance, gentle music.   1. #### **Paleness and Complexion Disorders (Al-Ṣafr)** Changes in complexion—such as pallor, yellowness, or darkness—indicate inner imbalance. Causes may be: - **Excess bile** (yellowness), - **Phlegm or spleen disorders** (paleness), - **Black bile excess** (darkening), - **Blood deficiency** (general loss of color). Treat through: - Restoration of humor balance, - Strengthening diet, - Use of color-enhancing herbs: **carrot**, **beet**, **parsley**, **saffron**.   1. #### **Fatigue and Weakness (Al-Ta****ʿ****ab wa-l-Da****ʿ****f)** General weakness may be due to: - Loss of humors, - Depletion of **innate heat**, - Excessive sexual activity, - Prolonged illness. Treatment requires: - Strengthening tonics: **asparagus**, **ginseng**, **goat’s milk**, **fenugreek soup**. - Sufficient sleep and regulated activity. - Avoidance of stimulants and overexertion.   1. #### **Sleep Disorders (Al-Nawm wa-l-Sahar)** - **Insomnia** (*sahar*): from excess heat, worry, or dryness. - **Excess sleep** (*nawm zā**ʾ**id*): from excess moisture, cold, or brain dullness. Remedies: - For insomnia: warm bath, milk with honey, poppy seed syrup. - For excessive sleep: stimulating odors (e.g., rose, mint), light exercise, massage.   **Chapter Seventeen:** ### **On the Compounding of Medicines (al-Aqrābādhīn)**   This discipline, known as **al-aqrābādhīn**, is the science of preparing and combining simple substances into **compound remedies** tailored to specific conditions and temperaments. It is the final and most practical section in the art of healing, where **theoretical knowledge** is translated into **therapeutic application**.   1. #### **Purpose and Importance** The rationale for compounded medicines is as follows: - A single drug may **lack the strength** to address a complex condition. - A simple remedy may act too aggressively, needing another to **moderate** its effect. - Some medicines require **correctives** (muṣaḥḥiḥāt) to reduce side effects. - Others need **carriers** (muwassilāt) to reach the target organ or humor. Thus, compound remedies are not mere mixtures, but **deliberately crafted formulas** guided by ratios, timing, and interaction of properties.   1. #### **Principles of Composition** The skilled physician follows these rules: - Each component should have a **purpose**: active ingredient, corrective, carrier, or flavoring. - The **temperament** (*mizāj*) of the final compound should match the patient’s constitution and condition. - The **quantity** and **order of mixing** matters: some ingredients are pre-cooked or infused, others added raw. - Remedies must be **balanced** between effectiveness and safety.   1. #### **Categories of Compound Remedies** 2. **According to Form**: - **Electuaries (ma****ʿ****ā****j****ī****n)**: thick pastes taken orally, e.g., *tiryaq*, *jawārish*. - **Syrups (sharābāt)**: decoctions in sugar or honey water. - **Powders (ghubrāt)**: dried and ground, often sprinkled or inhaled. - **Pills (****ḥ****ubūb)**: compacted forms for ease of use. - **Ointments (marhamāt)**: for external application. - **Enemas (****ḥ****uqan)** and **suppositories**: for cleansing and direct absorption. 1. ##### **According to Effect**: - **Laxatives (mushilāt)**, - **Diuretics (mubawwilāt)**, - **Tonics (muqawwiyāt)**, - **Digestives (hā****ḍ****imāt)**, - **Emetics (muqayyī****ʾ****ā****t)**, - **Refrigerants (mubarridāt)**, - **Warmers (mu****ḥ****arrikāt)**. Each is chosen based on the **humoral imbalance**, the **organ affected**, and the **seasonal or regional climate**.   1. #### **Examples of Famous Compounds** - **Tiryāq al-Fārūq**: antidote for poisons, made of opium, myrrh, cinnamon, honey, and over 60 ingredients. - **Jawārish Jālīnūs**: digestive, strengthens the stomach and liver. - **Lāuq**: soothing compound for the throat and chest. - **Thuflūṣ**: cold remedy made with licorice, figs, and poppy. Each is used in **measured doses**, usually starting from **half a dirham** up to **two**, depending on the patient’s strength and the drug’s potency.   1. #### **Storage and Administration** - Remedies must be stored in **dry, sealed containers**, away from light and heat. - Many lose their strength after **one lunar year**, some after just **forty days**. - Always give **with knowledge of timing**—some before food, others after. - For children, the dose is calculated in **proportion to age**, often one-third to one-fifth the adult dose.   #### **Conclusion of the Treatise** This completes the fivefold exposition of the art of medicine: 1. General Principles (*al-umūr al-kulliyyah*), 2. Simple Drugs (*al-adwiyah al-mufradah*), 3. Localized Diseases (*al-amrā**ḍ**al-juz**ʾ**iyyah al-waqi**ʿ**ah bi-**ʿ**u**ḍ**win**ʿ**u**ḍ**w*), 4. General Diseases and Adornment (*al-amrā**ḍ**allatī lam takhtaṣṣ bi-**ʿ**u**ḍ**w* wa-al-zīnah), 5. Compound Remedies (*al-aqrābādhīn*). It is incumbent upon anyone who claims the practice of this art to **know and preserve its essentials**, for it contains the **minimum necessary knowledge** for a physician to treat and heal. As for further refinements, they are many and diverse and belong to the realm of continued inquiry and mastery. --- ## **On the Categories and Degrees of Temperamental Moderation (al-I****ʿ****tid****ā****l)** Temperamental moderation may be considered in several ways: - **First**, it may be judged according to a **class within a species**, in relation to differences found **outside** of it but **within its type**. - **Second**, it may be judged according to a class **within itself** alone. - **Third**, it may be judged according to a **specific individual** within a class of a species, in relation to differences both **within** and **outside** its class and species. - **Fourth**, it may be judged by comparing the **person** to the various **states** or conditions **within himself**. - **Fifth**, it may be according to the **organ**, in relation to differences that are external to it but within the same body. - **Sixth**, it may be in relation to the **organ itself**, compared to its own internal conditions.   ## **The First Kind: Human Moderation Compared to All Other Creatures** This is the type of moderation by which the human being is compared to all other existents. It is a kind of **accidental moderation**, not confined to a precise definition. It is not arbitrary, but it has limits on either extreme—**excess and deficiency**—beyond which the temperament **ceases to be human**.   ### **The Second Kind: The Most Balanced Individual within a Class** This is the **median between the extremes** of the broad human temperament. It is found in the individual who has reached the peak of moderation **within the best class**, **at the age of full growth and maturity**. Though this is not **true or absolute moderation** (as described earlier), and although it is difficult or even impossible to attain, it nonetheless **approximates** true moderation. In such a person, the organs are in **equilibrium**: the **warm** organs (like the heart), the **cold** (like the brain), the **moist** (like the liver), and the **dry** (like the bones). When these are in balance, the temperament is close to true moderation. This applies **only to the organs**, except for the **skin**, which will be described later. However, with respect to the **spirits** (*arwā**ḥ*) and the **chief organs**, it is **not possible** for them to be in perfect moderation. They naturally tend toward **heat and moisture**, since the origin of life is the **heart and the vital spirit**, which are inherently hot and prone to excess. Life is sustained by **heat**, and growth by **moisture**; in fact, heat itself **depends on moisture** and is nourished by it. The **three primary organs** will be explained later. Of these: - The only **cold** organ is the **brain**, yet its coldness is insufficient to balance the heat of the heart and liver. - The only **dry** organ is the **heart**, but its dryness cannot temper the moistness of the brain and liver. - Nor is the brain **perfectly cold**, nor the heart **extremely dry**, but rather **relatively** cold or dry when compared to the others.   ### **The Third Kind: National or Ethnic Temperament by Region** This type is **narrower in scope** than species-level moderation, but still valid. It refers to the **temperament of a nation** suited to the **climate and air** of its region. For example: - **Indians** have a temperament suitable for **India**, by which they remain healthy. - **Slavs** have another temperament suited to **Slavic lands**, by which they are also healthy. Each is **moderate in relation to its own type**, but **not moderate** when judged by the other's standard. If a **Hindu body** acquires the temperament of a **Slav**, it will become ill or perish, and vice versa. Thus, every **population** has a temperament that suits the **climate** of its **region**.   ### **The Fourth Kind: The Median Within a Region** This is the **intermediate temperament** between extremes of climate in a given region—the most **moderate** among that population.   ### **The Fifth Kind: Individual Temperament for Bodily Integrity** This is **narrower** than both the species-level and ethnic temperaments. It is the **personal temperament** that must exist in a specific individual to ensure he is **alive and healthy**. It has boundaries, defined by **extremes of excess and deficiency**. Each person is entitled to a **unique temperament** so particular that it is **rarely—if ever—shared** by another.   ### **The Sixth Kind: The Optimal Personal Median** This is the **median** between excess and deficiency for an individual. If it is achieved, it is **the best possible state** that the person can attain.   ### **The Seventh Kind: Temperamental Requirements of Each Organ** Each **organ** has its own **distinct temperament**: - The **bone** should be **dry** in excess. - The **brain** should be **moist** in excess. - The **heart** should be **hot** in excess. - The **nerves** should be **cold** in excess. This kind of moderation has its own range, **less broad** than the previously mentioned types.   ### **The Eighth Kind: Optimum Moderation of Each Organ** This is the **most perfect** state for any given organ—when the organ attains **the optimal condition** for itself, balanced between its extremes. Thus, when considering all types, the **human species** is **closest** to true moderation. Among **ethnic groups**, those who inhabit regions around the **equatorial line**—if settled and not affected by extreme geographic features like **mountains** or **seas**—are **closest** to the true moderation. The belief that proximity to the **sun** causes deviation from moderation is **false**: direct overhead sun is **less disruptive** to the air than its oblique rays in other latitudes.   ---   ## **On the Skin and Its Unique Moderation** Among the organs, the **skin** is distinguished by being the **closest** to true moderation. In fact, it is even **closer** than flesh (*la**ḥ**m*), despite the latter also being very near to the balanced state. This is evident from the fact that **the skin hardly reacts** to a liquid composed of **equal parts of boiling and freezing water**. That is, when exposed to such a mixture, it does not show a significant reaction—neither from **the heating of the vessels and blood**, nor from **the cooling of the nerves**. Likewise, it does not react to a **perfectly blended substance** made from the **driest** and the **most fluid** bodies, if those qualities are equally mixed. This lack of response is **proof** of its temperamental balance. This lack of reaction is not because the skin lacks sensation, but rather because its temperament is **so similar** to that of the stimulus that **no opposition** occurs. For **opposing natures** provoke reaction, while **similar natures** do not. Only when there is **difference in quality** does sensation arise. Therefore, the **more balanced** the substance, the less likely it is to elicit a noticeable response.   #### **Hierarchy of Moderation in the Skin** - The **most balanced skin** is that of the **hand**. - Within the hand, the **palm** is the most balanced. - Within the palm, the **fleshy part** of the **fingers** is more balanced. - The **index finger** (*sabbāba*) has the most balanced skin among them. - On the index finger, the **fingertip (unmula)** is the most balanced point. This is why the **fingers**, especially the **fingertips**, are the **most precise instruments of touch**. They are the **judges** in discerning the **qualities** of tangible substances. A **proper judge** must be equally disposed toward both extremes, in order to detect **any deviation** from balance or moderation.   #### **Clarification Regarding Medicinal Temperament** When we say that a **medicine** is *moderate*, we do **not** mean that it is **truly and essentially moderate**, for such moderation is **impossible**. Nor do we mean that it matches the **human temperament** exactly—if it did, it would be of the **same essence** as the human body, which it is not. Rather, what we mean is that **when the natural heat** of the human body acts upon the medicine, and it responds with a **quality** that **does not deviate** markedly from the human constitution, then **its effect** is moderate. In other words, we call a substance *moderate* in relation to its **effect on the human body**, **not in its essence**.   #### **Degrees of Medicinal Heat and Cold** Similarly, when we say that a substance is *hot* or *cold*, we do **not** mean that it is **absolutely hot or cold** in essence, nor necessarily **hotter or colder than the human body**. Rather, we mean that it **produces heat or cold** in the body **beyond what is naturally present**. Thus, a medicine may be **cold in relation to the human body**, but **hot in relation to a scorpion’s body**. Or it may be **hot in relation to one person**, and **cold in relation to another**. For example, it may be **hot to Zayd**, but even **hotter to****ʿ****Amr**. This is why physicians are advised **not to persist with a single medicine** if it fails to produce the desired adjustment in temperament—it may simply not suit the **individual constitution**.   #### **Transition to the Discussion of Immoderate Temperaments** Now that we have fully examined the concept of **moderate temperament (i****ʿ****tid****ā****l)**, we may proceed to the study of **non-moderate** or **deviant temperaments** (*amzija ghayr mu**ʿ**tadila*). These, whether assessed by **species**, **group**, **individual**, or **organ**, all share the fact of being **opposed** to the balanced state. There are **eight forms** of these deviations, as we shall explain.   #### **The Eight Types of Non-Moderate (Deviant) Temperaments** (*al-amzija al-ghayr mu**ʿ**tadila*)   Just as there are degrees and types of moderation, there are also **eight categories** of **non-moderate (deviant) temperaments**, all of which share a departure from the balanced state. These can be understood as either: - **Simple deviations**, where imbalance occurs along a **single axis** (e.g., only heat or only dryness), or - **Compound deviations**, where imbalance occurs **along two axes** simultaneously (e.g., heat and dryness together).   ##### **Simple Deviations: Along a Single Opposition** These occur in relation to **one pair of opposites** (*mu**ḍ**āddayn*), either in the **active qualities** (heat/cold) or the **passive qualities** (moisture/dryness). ##### **Deviations in Active Qualities (Heat/Cold)** These are of two kinds: - A temperament that is **hotter than it should be**, while not being **drier or moister** than it should be. - A temperament that is **colder than it should be**, while also remaining neutral in terms of moisture and dryness. ##### **Deviations in Passive Qualities (Dryness/Moisture)** These also fall into two cases: - A temperament that is **drier than it should be**, without being hotter or colder than it should be. - A temperament that is **moister than it should be**, without being hotter or colder.   #### **Instability of Pure Deviations** These **four simple types** of deviation **do not remain stable** for long, because: - Excess **heat** tends to **dry** the body over time, resulting in a combined hot-dry temperament. - Excess **cold** leads to **moisture retention**, resulting in a cold-moist temperament. - **Dryness** often progresses to **coldness**, as the lack of moisture weakens heat. - **Moisture**, especially in excess, tends to **cool** the body, either by overabundance or eventual dispersion of innate heat. Thus, these single deviations tend to **evolve** into **compound deviations** unless corrected.   #### **Conclusion of the Four Simple Deviations** From this we understand that **moderation** and **health** are more naturally aligned with **heat** than with **cold**, because coldness often leads to stagnation and decay. These four simple imbalanced types are the **first half** of the eightfold division. The remaining four are the **compound deviations**, in which two qualities are unbalanced simultaneously. 1. **Compound Deviations: Along Two Oppositions Simultaneously** These are the **other four** types of **non-moderate (imbalanced) temperaments**, where deviation occurs **in both pairs** of opposing qualities: that is, **heat and cold** as active qualities, and **moisture and dryness** as passive ones. In these cases, the imbalance is **not limited** to one axis but spans **two axes** at once. There are **four compound deviations**:   1. ##### **Hot and Dry (****ḥ****ār yābis)** This is the temperament where **heat** and **dryness** both exceed their proper bounds. It can be observed in: - Bodies with excessive metabolic activity, - Strong pulse, - High energy, but with dryness in skin, joints, and organs. This type is often associated with **youth in hot, arid climates**, or those who consume **spicy and desiccating foods**.   1. ##### **Hot and Moist (****ḥ****ār ra****ṭ****b)** Here, **heat** is combined with **excess moisture**. Such a body is: - Warm to the touch, - Moist in secretions and excretions, - Prone to inflammation, swelling, and febrile conditions. This is typical of **early youth**, or people living in **humid tropical regions**, especially if they consume **rich and wet foods**.   1. ##### **Cold and Moist (bārid ra****ṭ****b)** A temperament where **coldness** and **moisture** are both in excess. Features include: - Sluggish digestion, - Pale complexion, - Lethargy and retention of fluids, - Tendency toward phlegmatic diseases. This is common among the **elderly**, or people in **cold, damp environments**, or those who overindulge in **cold-moist foods** like cucumbers, dairy, or excess water.   1. ##### **Cold and Dry (bārid yābis)** This is the most **static** and **debilitating** of the compound types. Signs include: - Cold extremities, - Dry skin and membranes, - Poor circulation, - Low energy and weak digestion. It is typical of **old age**, or those exposed to **chronic cold and wind**, or who consume a diet lacking in nourishing heat and moisture.   ##### **Summary of the Eight Temperaments** To summarize, all imbalanced temperaments—whether simple or compound—fall into one of these **eight categories**: 1. Excess heat 2. Excess cold 3. Excess moisture 4. Excess dryness 5. Hot-dry 6. Hot-moist 7. Cold-moist 8. Cold-dry Each has its own signs, causes, and remedies, and none can be ignored when diagnosing illness or prescribing treatment. --- **Section:** ### **On Compound Temperaments and Their Causes** Compound temperaments arise when there is deviation in **both axes of opposition**—that is, in the active (heat/cold) and passive (moisture/dryness) qualities. Examples include a temperament that is: - **Hot and moist** at the same time beyond the appropriate limit, - Or **cold and moist** beyond what is proper, - Or **cold and dry** likewise. It is not, however, possible for a temperament to be **hot and cold** at the same time, nor **moist and dry** simultaneously. Each of these **eight temperaments** (four simple and four compound) may exist: 1. **Without an accompanying material substrate**, meaning that the temperament manifests merely as a quality (*kayfiyyah*) in the body without the body being altered by the presence of an actual substance (humor). This is akin to the **heat produced by pounding** or the **coldness felt in frostbitten loins**—effects of external causes, not internal substance. 2. **With a material substrate**, meaning the body adopts this temperament due to the **presence and penetration** of a dominant **humor** possessing that very quality. For example: - The body is cooled by an excess of **glassy phlegm**, - Or heated by an excess of **sharp yellow bile (ṣafrā****ʾ****karr****ā****thiyyah)**. You will find in the **third and fourth books** examples of each of these sixteen temperaments.   **Section:** ### **Material Substrates and their Effects** Know that when temperament arises **with a material cause**, it may take two forms: 1. The organ may be **directly infused** and permeated by the humor. 2. The material may be **retained within its passages and cavities**, in which case: - It may cause **inflammation or swelling**, - Or it may not, depending on the conditions.   **Section:** ### **Temperaments of the Organs** Know that the **Creator**, exalted be His majesty, has given to every animal and every organ the temperament **most suited** and **most effective** for performing its proper functions, to the extent possible. Establishing this principle fully belongs more to the **philosopher** than the **physician**. As for the human being, he was given **the most balanced temperament** possible in this world, suited to the **powers** by which he acts and reacts. Each **organ** was given the temperament most suited to its function. Thus, some organs are: - **Hotter**, some **colder**, - Some **dryer**, some **moister**.   **Section:** ### **Ranking of the Organs by Heat** The **hottest** entities in the body are: 1. The **spirit (rū****ḥ****)** and the **heart**, where it originates, 2. Followed by the **blood**, which, although generated in the liver, derives its heat from its contact with the heart, 3. Then the **liver** itself, which is like **congealed blood**, 4. Then the **lungs**, 5. Then the **flesh**, though it is less hot due to being mixed with **nerve fibers**, which are cold, 6. Then the **muscles**, which are less hot than plain flesh due to the addition of **nerves and ligaments**, 7. Then the **spleen**, due to the **impurities** of the blood within it, 8. Then the **kidneys**, due to their relatively low blood content, 9. Then the **layers of pulsating arteries**, not because of their own substance, but due to the **heat of the blood and spirit** flowing through them, 10. Then the **layers of still veins**, warmed only by the **blood**, 11. Then the **skin of the palm**, which is of **moderate** temperament.   **Section:** ### **Ranking by Coldness, Moisture, and Dryness** #### **Coldest Substances:** 1. **Phlegm**, the coldest, 2. Then **fat (sha****ḥ****m)**, 3. Then **hair**, 4. Then **bone**, 5. Then **cartilage**, 6. Then **ligament**. #### **Moistest Substances:** 1. **Phlegm**, 2. Then **blood**, 3. Then **fatty tissue**, 4. Then **fat (sha****ḥ****m)**, 5. Then the **brain**, 6. Then the **spinal cord**, 7. Then the **flesh of the breasts and testicles**, 8. Then the **lungs**, 9. Then the **liver**, 10. Then the **spleen**, 11. Then the **kidneys**, 12. Then the **muscles**, 13. Then the **skin**. This is the ordering **according to Galen** (*Jālīnūs*).   #### **Clarification on the Lungs’ Moisture** It must be noted that the **lungs**, in their **substance and innate disposition**, are not extremely moist. This is because every organ's **innate temperament** resembles the nature of **what it feeds upon**, and its **accidental temperament** resembles what is **excreted from it**. The lungs feed upon the **hottest blood**, rich in **yellow bile**, as Galen confirmed. Yet they accumulate **a great deal of extraneous moisture**, due to: - Vapors ascending from the body, - Mucus draining down into them. Thus, while the **liver** is **more moist innately**, the **lungs** are **more frequently soaked**, which might render them effectively moister over time.   #### **Distinction Between Types of Moisture** The **moisture of phlegm** is mostly of the **soaking kind** (*bilal*), The **moisture of blood** is mostly of the **constitutive kind** (*taqrīr fī al-jawhar*). Phlegm is **naturally more moist**. But when it transforms into blood through digestion, it **loses much of its original moisture**. Thus, **natural phlegm** is essentially **immature blood** that has not completed its transformation.   **Section:** ### **Ranking of Organs by Dryness** The **driest** entity in the body is: 1. **Hair** – produced from **smoky vapor** whose humidity has dissipated, leaving behind a **purely dry essence**, 2. Then **bone**, the hardest organ—but though **harder than hair**, it is **less dry**, as proven by: - When equal weights of bone and hair are **distilled**, bone yields **more water and fat**, indicating it retains more moisture. 3. After bone comes **cartilage**, 4. Then **ligament**, 5. Then **tendon**, 6. Then **membrane**, 7. Then **arteries**, 8. Then **veins**, 9. Then **motor nerves**, 10. Then the **heart**, 11. Then **sensory nerves**. - **Motor nerves** are significantly **colder and drier** than the balanced mean. - **Sensory nerves** are **colder**, but not greatly drier—possibly even **close to balance** in dryness. After that comes the **skin**.   This concludes the **second chapter** (fāṣl al-thānī) on the **temperaments of organs**. I will continue next with the **third chapter** on the **temperaments of ages and sexes**, beginning with the classification of life stages (*asnan*) and the associated temperaments. --- **Chapter Three:** ## **On the Temperaments of Life Stages and Genders** Human life, in general, can be divided into **four main stages**: 1. **The Age of Growth (Sinn al-Namā****ʾ****)** — also called **childhood (****ḥ****adātha)**, which extends up to around **thirty years**. 2. **The Age of Stability (Sinn al-Wuqūf)** — the period of **youth (shabāb)**, lasting until about **thirty-five or forty years**. 3. **The Age of Decline with Retained Strength** — known as **middle age (mukta****ḥ****ilīn)**, extending until about **sixty years**. 4. **The Age of Decline with Manifest Weakness** — known as **old age (shaykhūkhah)**, from then until the end of life. **Subdivisions of the Age of Growth** 1. **Infancy (****ṭ****ufūlah):** when the newborn’s organs are still unprepared for movement and standing. 2. **Childhood Proper (ṣibā):** after the child can rise and walk, but before all teeth have fallen and regrown. 3. **Youthful Bloom (tararra****ʿ****):** after full teething and strength, but before adolescence. 4. **Adolescence and Early Youth (ghulāmiyyah and rahāq):** until facial hair begins to appear. 5. **Young Adulthood (futūwah):** until growth is fully completed.   ### **Temperaments in Children and Youth** Children and adolescents generally have a **moderate temperament in heat**, but an **excess in moisture** due to the requirements of growth. There is **disagreement** among earlier physicians regarding which age has **greater natural heat**—the child or the youth: - Some say that **children are hotter**, explaining: - Their growth is more rapid, - Their natural functions (e.g., appetite, digestion) are more vigorous, - Their innate heat is newer and more concentrated from seminal origin. - Others say that **youth are hotter**, arguing: - Their blood is **more abundant and robust**, - They are more prone to **nosebleeds (ru****ʿ****ā****f)**, - Their temperament inclines toward **yellow bile (ṣafrā****ʾ****)**, while children incline toward **phlegm (balgham)**, - They have **stronger motion and digestion**, which are signs of greater heat. As for **desire (shahwah)**, it is **not caused by heat**, but rather by **coldness**—which is why **canine lust** is more frequent in cold temperaments. However, such lust is not accompanied by good digestion or assimilation. Children, in contrast, **digest well**, which disproves the cold-lust theory.   ### **Galen’s Position** **Galen** refutes both sides. He states that: - The **quantity of heat** is **greater** in children, - But the **quality (sharpness)** of heat is **stronger** in youths. He gives the analogy of **equal amounts of heat** diffused in: - A **moist substance** like water: yields **greater quantity** but **milder quality**, - A **dry substance** like stone: yields **less quantity** but **sharper intensity**. Thus, heat in children is like that in **hot water**, while in youth it's like **hot stone**—less in amount, more in sharpness. Children are still increasing and growing—heat has not declined. Youth are at the stage of **conserving heat**, with **less moisture** to protect it.   ### **Decline of Heat with Age** After the **age of stability**, innate heat begins to **decline**, due to: - The **external air** drying up internal moisture, - The weakening of **natural resistance** to loss, - The increasing **physical and emotional exertions** required by life. All **bodily powers** are finite. Their action and renewal **cannot be constant**. Thus, **evaporation and decay** begin to **exceed replenishment**, and innate moisture is lost more quickly. Eventually, there is **not enough moisture** to: - Sustain **heat**, or - Sustain **growth**. At this point, **decline** becomes inevitable.   ### **The Nature of Natural Death** This **natural death** is the result of: - Diminishing internal **moisture**, - The **extinguishing of innate heat**, - The emergence of **foreign cold moisture**, which: - Smothers innate heat (*by immersion*), - Or opposes it in nature (*by antagonism*), - This foreign moisture is **phlegmatic and cold**. Thus, death is the extinguishing of the **innate fire** due to lack of **fuel** (moisture) and **the assault of cold**. Every person has a **specific natural lifespan**, dependent on their **temperament**.   ### **Comparative Summary of Life Stages** - **Children and youths**: hot by temperament, - **Children** are **more moist** (due to growth), - Evident from the **softness** of their bones and nerves, - **Adults and elders**: - **Colder**, and - **Drier** than the moderate standard, - Evident in **hard bones**, **dry skin**, and diminished fluids. Youth are **more moderate** than children, but drier by comparison. They are **hotter than elders**, while elders are **drier** by their original temperament, and sometimes **moister** due to accumulation of **foreign moisture**.   ### **Temperaments of the Sexes** - **Women** are **colder** and **more moist** than men, - Hence their **smaller size**, and - Their **greater residue accumulation**. - Their muscles are less dense, and their flesh more spongy. - Men’s flesh, although coarse due to nerve and vessel content, is **cooler** due to its density and penetration by vessels.   ### **Temperaments by Region and Occupation** - People of **northern regions** are **more moist**. - Those in **watery trades** (fishermen, etc.) are also moister. - Their **opposites** are drier.   ### **Conclusion and Next Steps** This completes the third chapter on **age, gender, and temperament**. The text indicates that next will come **signs (****ʿ****al****ā****m****ā****t)** of temperaments—**both general and specific**. --- **Chapter Four:** ## **On the Humors (al-Akhlā****ṭ****)** **Section One:** ### **The Nature of Humor and Its Types** #### **Definition of Humor (al-Khal****ṭ****):** Humor is defined as a **fluid and moist substance** into which food is initially transformed during digestion. Among humors, there are those that are **beneficial** (maḥmūd) and those that are **harmful** (radiʾ). - A **beneficial humor** is one that is capable of becoming, either alone or in conjunction with others, a part of the essence (*jawhar*) of the nourished body. It assimilates fully or partially into the bodily structure, and serves to **replace** what has been lost through natural decay. - A **harmful humor** is one that **lacks** this capacity by nature. It may rarely transform into a beneficial humor, but its proper course is **to be expelled** from the body. We classify the body's moistures into **primary** and **secondary** types: 1. **Primary moistures** are the **four canonical humors** which will be described in detail below. 2. **Secondary moistures** are of two kinds: - **Superfluous** (faḍlī) – to be detailed later. - **Non-superfluous** – which are themselves of **four varieties**: - (i) Moisture trapped within the cavities at the ends of the vessels. - (ii) Moisture diffusely spread throughout the main organs, akin to dew; it is ready to be transformed into nourishment when food is absent, or to rehydrate the body if desiccated by vigorous motion or other causes. - (iii) Moisture recently integrated into the organs through the process of digestion and assimilation, but not yet fully transformed into a solid component. - (iv) Inherent moisture within the essential organs from the very beginning of formation – originating in the sperm and thus ultimately in the humors. Furthermore, both **beneficial** and **superfluous** humoral moistures are grouped into **four main types**: 1. **Blood (dam)** – the **most noble** of the humors. 2. **Phlegm (balgham)** 3. **Yellow bile (ṣafrā****ʾ****)** 4. **Black bile (sawdā****ʾ****)** #### **On Blood (al-Dam)** **Blood** is warm (*ḥ**ār*) and moist (*ra**ṭ**b*) by nature, and it is divided into **two types**: - **Natural blood** - **Unnatural blood** #### **Natural Blood:** It is bright red in color, not foul-smelling, and extremely sweet in taste. This is the healthy, nourishing form of blood. #### **Unnatural Blood:** This is divided into two categories: 1. That which has **deviated from its healthy temperament**, **not due to any admixture**, but due to an internal imbalance in its own temperament. For instance, the blood may have become too cold or too hot on its own. 2. That which has changed **because of a bad humor mixing with it**, and this is itself of two kinds: - A foreign humor has **entered from outside** and corrupted it. - A **putrefaction** has arisen **within the blood itself**, causing part of it to decay. For example, one layer may become bitter yellow bile (*murrat ṣafrā**ʾ*), another may become thick black bile (*murrat sawdā**ʾ*), or remnants of either may remain within. This second category is highly variable depending on what has mixed with the blood. It may take on characteristics of **phlegm**, **black bile**, **yellow bile**, or **watery moisture**. Thus, the blood may appear: - **Cloudy (****ʿ****akir)** - **Watery (raqīq)** - **Deep black** - **White** Likewise, it may change in: - **Odor** (becoming foul) - **Taste** (becoming bitter, salty, or acidic)   #### **On Phlegm (al-Balgham)** Phlegm, too, is of **two kinds**: - **Natural** - **Unnatural** #### **Natural Phlegm:** This is the type that can, at a certain stage, **transform into blood**—because it is **blood that has not fully matured**. It is a kind of **sweet phlegm**, not extremely cold, and when compared to the body, it is only **mildly cold**—but compared to **blood and yellow bile**, it is colder. Sometimes, sweet phlegm that is **not natural** may be found. This is the kind **without any taste**, which we will mention later when it mixes with natural blood. It is frequently observed in **catarrhs (nazalāt)** and **hemoptysis (nafth)**. As Galen stated, the reason nature did not assign a specific organ for the excretion of this phlegm (as it did for the two bile types) is because this phlegm closely resembles blood, and **all organs need it**, so it circulates with the blood. We say the body **needs** this phlegm for **two main purposes**: 1. **Necessity**, which is twofold: - To serve as a **reserve** near the organs, so that whenever they are **deprived of incoming nourishment**, this phlegm **converts into usable blood**—thanks to **innate heat** acting on it from the stomach or liver, allowing the body to feed from it. - Though **innate heat** can transform it into blood, **foreign heat** (excessive or pathological) can **corrupt it** and lead to putrefaction. Note: The two biles **cannot** be transformed into blood via innate heat as phlegm can—though all three can become putrid via **external heat**. 1. To **blend with the blood** and prepare it for nourishing **organs with phlegmatic temperaments**, which require their blood to contain an actual phlegmatic portion—like the **brain**. This function **is shared with the bile types**. #### **Benefit (Manfa****ʿ****a):** Phlegm **moistens joints** and **highly mobile organs**, preventing them from **drying out** due to motion or friction. This benefit lies at the intersection between necessity and utility.   #### **Unnatural Phlegm (al-Balgham ghayr al-****ṭ****abī****ʿ****ī****)** Unnatural phlegm includes **excessive** and **qualitatively deviant** types. These may differ: - In **consistency**, even perceptibly to the senses, such as: - **Mucous (mukhā****ṭ****ī)** phlegm - **Raw (khām)** phlegm: apparently uniform in texture but in fact abnormal - **Very thin**, watery phlegm - **Very thick**, known as **"gypsum-like" (al-jussī)** phlegm: this has undergone significant change due to **long retention in joints and passages**, becoming the thickest and most compact type. There is also: - A **salty phlegm**: this is **hotter**, **drier**, and **tougher** than all other types. The cause of saltiness is the **mixing** of a slightly or flavorless **watery moisture** with **burnt earthy elements** that are **dry**, **bitter in taste**, and **balanced in proportion**. If excessive, the result is bitterness. This is also how **salts** are produced and how **water becomes salty**. Salt can even be made artificially by: - Boiling **ash**, **alkaline substances**, or **nūrah** (a type of lime) in water, straining it, and evaporating until salt remains. Similarly, **thin phlegm**, lacking taste or with faint flavor, when mixed with **naturally dry and burnt bitter bile**, may turn **salty** and **heated**, becoming what is known as **saffron-like phlegm** (*balgham ṣafrawī*). According to Galen, this phlegm becomes salty **due to putrefaction** or the **presence of watery moisture**. We say: **putrefaction** causes saltiness through **burning and ashing**, mixing ash with moisture. But **watery moisture alone** does not produce saltiness **unless** the **secondary factor** (i.e., burning) is also present. There is also: - **Sour phlegm (****ḥ****āmi****ḍ****)**: like sweet phlegm, it can be: - **Inherently sour**, or - **Made sour through external contamination**, especially from sour black bile (we will mention it later). Sometimes, **sweet phlegm** or phlegm on the path toward sweetness, undergoes **fermentation**, and then **acidification**, as is the case with other sweet juices. - **Astringent phlegm (****ʿ****afṣ)** may also occur. This can arise from: - Admixture with **astringent black bile** - Or due to phlegm itself becoming **extremely cold**, turning its flavor **astringent** due to the **freezing** of its watery content and conversion into **dryness and earthiness**. In this case, **moderate heat** won’t suffice to **boil and sour it**, nor can **strong heat** **mature it** properly. There is also a **glassy**, thick phlegm, **viscous and heavy**, resembling **molten glass**. It can be: - **Sour** - **Insipid** The thicker, insipid version may in fact be **raw phlegm** or develop into it. This glassy type arises from phlegm that was initially **watery and cold**, but was: - **Not putrefied** - **Not contaminated** - **Simply suffocated**, becoming **thicker and colder** over time. Hence, the **flavors** of **corrupt phlegm** are four: - **Salty** - **Sour** - **Astringent** - **Insipid** And its **textures** are also four: - **Watery** - **Glassy** - **Mucous** - **Gypsum-like** The **raw** kind is often a precursor to the **mucous** type.   #### **Yellow Bile (Ṣafrā****ʾ****)** Yellow bile is of two types: - **Natural (****ṭ****abī****ʿ****ī****)** - **Excess and unnatural (fa****ḍ****l ghayr****ṭ****abī****ʿ****ī****)** The **natural yellow bile** is the *froth of the blood*. It is **bright red**, **light**, and **sharp** in nature. The hotter it is, the more intensely red it becomes. When it is produced in the **liver**, it splits into two parts: 1. One part **accompanies the blood**, and 2. The other part is **filtered** into the **gallbladder**. The portion that **flows with the blood** does so **out of necessity and benefit**: - **Necessity**: Because it must mix with the blood in nourishing certain organs that require a portion of yellow bile in their temperaments—like the **lungs**. - **Benefit**: It *thins the blood* and *helps it penetrate narrow vessels*. The portion that is **filtered into the gallbladder** also serves a **necessary and beneficial** purpose: - **Necessity**: - For the **entire body**: It purges the body of excess. - For the **gallbladder**: It nourishes the organ itself. - **Benefit**: It serves **two main functions**: 1. It **cleanses the intestines** of dregs and sticky phlegm. 2. It **stimulates the intestines and the rectal muscles**, triggering the urge to defecate. For this reason, if yellow bile accumulates excessively, it may lead to **colic (qawlanj)**. #### **Unnatural Yellow Bile** The unnatural type is of **two categories**: 1. That which deviates from its natural form **due to foreign admixture**. 2. That which is **inherently unnatural in essence**. The first category includes: - The **well-known** type resulting from yellow bile **mixed with phlegm**, usually formed in the **liver**. - The **lesser-known** type formed from yellow bile **mixed with black bile**. The well-known types are: - **Acrid yellow bile (al-mirrah al-ṣafrā****ʾ****)** - **Milky bile (al-mirrah al-mu****ḥ****īyah)** This distinction arises from the type of phlegm it mixes with: - If the phlegm is **thin**, it produces **acrid yellow bile**. - If it is **thick**, it resembles the **white of an egg**. The **lesser-known** type is what is called **burnt yellow bile (ṣafrā****ʾ****mu****ḥ****taraqa)**, and it appears in two forms: 1. **Yellow bile burns within itself**, developing a grayish quality, with ash retained inside it. This is the **worst type**, and is termed *burnt bile* in medical treatments. 2. **Black bile enters from outside** and mixes with yellow bile. This is the **milder case**. The color of this type of bile is **red**, but not bright or brilliant—more like **blood**, but thinner. Its color may change for various reasons. As for yellow bile that is **inherently unnatural**, it arises in two main places: - Mostly in the **liver** - Or mostly in the **stomach** The type formed in the **liver** is **one kind**: when the **fine part of blood is burned**, leaving behind the coarse part which becomes **black bile**. The type formed in the **stomach** is of two kinds: 1. **Leek-like bile (karrāthī)**: probably produced by the burning of the **egg white-like phlegm**, which when burned turns **green**—a mix of yellow and black. 2. **Verdigris-like bile (zanjārī)**: this appears to form from the further burning of the *leek-like* bile. Its moisture is lost, it begins to turn **white**, and this follows a natural thermal progression: First heat darkens wet substances → they become **black** Excess heat dries and **bleaches** them → they become **white** Think of what happens to **wood** when burned: - First it turns **charcoal black**, then **ash white**. This green-blue bile is: - The **hottest** type of yellow bile - The **most harmful** - The **most deadly** It is believed to contain elements of **poison**.   #### **Black Bile (Sawdā****ʾ****)** Black bile is also of two types: - **Natural (****ṭ****abī****ʿ****ī****)** - **Excess / unnatural (fa****ḍ****l ghayr****ṭ****abī****ʿ****ī****)** The **natural black bile** is the **sediment and dregs** of praiseworthy blood. Its taste lies **between sweetness and astringency**. When it forms in the **liver**, it divides into two portions: 1. One part flows with the blood. 2. The other heads toward the **spleen**. The part that **circulates with the blood** does so out of **necessity and benefit**: - **Necessity**: It **mixes with the blood** in the **right amount** to nourish organs that require a component of black bile in their temperament—such as the **bones**. - **Benefit**: It **fortifies the blood**, **thickens it**, and **prevents its dissipation**. The part that travels to the **spleen**—the portion **no longer needed by the blood**—also goes for necessity and benefit: - **Necessity**: - For the **whole body**: It is purged as excess. - For the **spleen** itself: It is used as nourishment. - **Benefit**: When the spleen breaks it down and **transmits it to the mouth of the stomach**, two effects occur: 1. It **tightens** and **strengthens** the stomach’s opening. 2. Its **sourness stimulates the appetite** by provoking hunger. Note: - The **yellow bile discharged into the gallbladder** is what the blood **does not need**. - The **yellow bile discharged from the gallbladder** is what the gallbladder **no longer needs**. - The **black bile sent to the spleen** is what the blood **does not need**. - The **black bile discharged from the spleen** is what the spleen **does not need**. Just as **yellow bile descending** from the gallbladder **stimulates downward propulsion**, so too **black bile ascending** from the spleen **stimulates upward attraction**. Thus: “Blessed is God, the best of creators and the wisest of judges.”   #### **Unnatural Black Bile (Fa****ḍ****liyya Ghayr****Ṭ****abī****ʿ****iyya)** Unnatural black bile is that which arises **not by way of sedimentation and residue**, but rather **through charring and combustion**. Substances that are moist but intermixed with earthy elements can distinguish their earthy part in one of two ways: - Either through **sedimentation**, such as in the case of **blood**, resulting in **natural black bile**, - Or through **burning**, in which the lighter components are consumed and the dense ones remain—this is the **excess black bile** formed by combustion, called **scorched black bile (al-mirra al-sawdā****ʾ****al-i****ḥ****tirāqiyya)**. Sedimentation occurs only with blood, because: - **Phlegm**, due to its viscosity, does not deposit residue like dregs. - **Yellow bile**, due to its subtlety and low earthy content, its constant motion, and the small amount of matter that separates from it in the body, produces **no appreciable sediment**. If any separation does occur, it either **quickly decays** or is **discharged**. - When it decays, its subtle parts dissipate, and the dense remainder becomes **combusted black bile**, not sedimentary. As for the types of **excess black bile**, they are several: 1. **Ash of yellow bile**, which is its residue after combustion. It is **bitter**. - The difference between this and the “burnt yellow bile” previously described is that the **burnt yellow bile** is **still mixed** with this ash, whereas **this ash** is **fully separated** and burned. 2. **Ash of phlegm**, depending on its nature: - If the phlegm is very light and watery, its ash tends toward **saltiness**. - Otherwise, the ash may be **sour** or **astringent**. 3. **Ash of blood**, which is **salty with a slight sweetness**. 4. **Ash of natural black bile**: - If this bile was **thin**, its ash becomes **extremely acidic**, like **vinegar boiling on the surface**, **pungent in smell**, and able to repel flies and the like. - If it was **thick**, the ash is **less acidic**, with a mixture of **astringency and bitterness**. In sum, the types of **corrupted black bile** fall into **three** categories: - **Burnt yellow bile** after its subtle components have been consumed. - The two types of ash mentioned above. As for **phlegmatic black bile**, it is **slower to cause harm** and **less corrupt**. If we rank the **four humors by the harmfulness** of their combustion: 1. **Black bile** is the **most dangerous** and **most harmful**. 2. **Yellow bile** spoils **most rapidly**, but is also **more treatable**. 3. Of the remaining two (phlegm and blood): - The one that becomes **most acidic** is **worse**, but still **more manageable** if treated early. - The other is **less volatile**, **slower to damage**, but also **slower to heal**.   Galen said: *Those who claim that the only true humor is blood and that all others are superfluities without any beneficial use are mistaken.* For if blood alone were the humor that nourishes the organs, then **all organs would be identical** in temperament and composition. But this is not the case: - **Bones** are harder than **flesh**, because the blood that nourishes them is mixed with a dense, earthy, **black bile-like essence**. - **The brain** is softer than other organs, because its nourishing blood is mixed with a **phlegmatic, moist essence**. Indeed, **blood itself** is always **intermixed** with the other humors. When it is extracted and allowed to settle in a vessel, it **separates visibly** into four parts before the eye: 1. A **frothy layer** — this is **yellow bile**. 2. A **whitish layer** — this is **phlegm**. 3. A **sediment or dregs** — this is **black bile**. 4. A **watery component** — this is **the watery humor** (al-māʾiyya), whose excess is expelled in **urine**. This **watery humor** is not considered one of the four humors. It is derived from **ingested liquids** that do **not nourish** the body. Rather, it serves the **purpose of thinning** the nutritive substance and enabling its **penetration** into the organs. As for the **humor proper**, it is derived from **nutritive food and drink**, and we say it is **nutritive** (*ghādd*) because it **resembles the body in potentiality** (i.e., it is capable of becoming like the body). The substance that has the potential to resemble the human body is not **simple**, but **composite**. Water, being a **simple** substance, cannot by itself nourish the human body. Some people think that the **strength of the body** depends on the **quantity of blood**, and that weakness is due to a **deficiency** in it. But that is not the case. What truly matters is **how much of the blood the body can successfully assimilate**—that is, **its quality**, not merely its quantity. Others believe that **if the ratios among the humors remain balanced**, then health is preserved—even if the absolute amounts of the humors fluctuate. But this is also incorrect. Each humor must maintain not only its **relative balance** with the others but also its **own absolute quantity** as required by the body. There remain certain debates concerning the humors that are **not appropriate** for physicians to engage in, as they **fall outside the scope of medical science** and are more properly addressed by **philosophers**. Thus, we have **abstained** from discussing them here. --- **Chapter Two:** ## **On the Generation of the Humors** Know that food undergoes digestion in multiple stages. The first digestion occurs through **chewing**. This is because the inner surface of the mouth is **continuous** with the inner surface of the stomach—almost as though they share one surface. The mouth possesses a **digestive power**, so when the chewed matter (*al-mam**ḍ**ūgh*) comes into contact with it, it undergoes a kind of transformation. Assisting in this is the **saliva**, which itself is warmed by **innate heat** and contributes to the initial maturation of the food. This is why **chewed wheat** can mature and draw out infections in boils and abscesses in a way that ground or boiled wheat cannot. They say: The evidence that chewed food begins to digest is that its **original taste and smell disappear**. When it reaches the **stomach**, it undergoes **further digestion**, not solely by the stomach’s own heat, but also by the **heat of the surrounding organs**: - On the **right side**, the **liver**. - On the **left side**, the **spleen**, which is warmed not by its own essence, but by the **abundant arteries and veins** that traverse it. - **In front**, the **omentum** (*al-thirb*), a fatty membrane that easily receives heat due to the **fat** it holds, conducting it to the stomach. - **Above**, the **heart**, which warms the **diaphragm**, and in turn supports the digestive process. When this **first digestion** is complete, the substance becomes, in most animals and with the aid of the drink taken alongside it, a liquid called **chyle** (*kīlūs*): a flowing substance resembling thick **barley water** or **fermented yogurt water**, smooth and white. From there, the chyle’s **lighter portions** are drawn from both the stomach and intestines via the **mesenteric vessels** (*masārīqā*), which are fine, firm veins connected to the intestines. These transport it to the **portal vein** (*bāb al-kabid*), which leads to the **liver**. The **portal vein** has **many fine branches** that reach deep into the liver, like delicate threads. These tiny branches connect to the **roots** of the **ascending vein** (*al-**ʿ**irq al-**ṭ**āli**ʿ*) emerging from the upper convexity of the liver. This fine distribution ensures that **the liver, in its entirety, is in contact with all of the chyle**, enhancing its action and speeding up the process. There, the chyle is **cooked**—and every such cooking produces: - **Foam**, which becomes **yellow bile**, - **Sediment**, which becomes **black bile**, - And if the cooking is excessive: a portion may become **burnt**, producing harmful forms of bile and black bile. - If the cooking is incomplete, a portion remains **raw**, which becomes **phlegm**. The **well-digested, purified portion** becomes **blood**. However, while still inside the liver, this blood is **thinner than ideal**, due to an excess of **watery fluid** needed for a reason we will explain. When this blood separates from the liver, the **excess water**—which was needed earlier but is now superfluous—is **drawn away** through a **descending vein** toward the **kidneys**, carrying with it a portion of the blood sufficient to **nourish** the kidneys with its **fatty and red** content. The rest becomes **urine** and passes to the **bladder and urethra**. As for the **well-formed blood**, it flows through the **ascending vein** from the top of the liver, then into **branching veins**, which in turn divide into smaller branches, then into even finer channels, until they reach the **capillaries** and finally **seep out** into the organs—**by the precise measure of the All-Knowing Creator**. Thus, the **active cause** of blood is **moderate heat**. Its **material cause** is **balanced and high-quality food and drink**. Its **formal cause** is **proper maturation**. Its **final cause** is **the nourishment of the body**. As for **yellow bile**, its **active cause** is also moderate heat—if it is the **natural kind** (i.e., the froth of blood). But if it is the **burnt kind**, its cause is **excessive, fiery heat**, especially in the **liver**. Its **material cause** is fine, hot, fatty, sweet, or sharp foods. Its **formal cause** is **overcooking**, surpassing proper maturation. Its **final cause** is the same **necessity and benefit** mentioned earlier.   As for **phlegm**, its **active cause**—for the *natural kind*, which is the incomplete stage of blood—is a **weaker or insufficient heat** that doesn't fully transform the chyle into blood. Its **material cause** is **moist, cold, or sweet foods**, and **thick drinks**. Its **formal cause** is **deficiency of heat** in the liver that fails to digest the chyle completely. Its **final cause** includes: - The body's need to **moisten the joints** and prevent **dryness** from motion and friction; - The necessity to **aid in digestion** if food is lacking or excessive activity occurs; - Its **blend** with blood, especially in organs that require a more **moist temperament**, such as the **brain**. Now, for the **non-natural forms of phlegm** (i.e., excess or corrupt phlegm), their causes differ. These include: - Weak digestion, - Overeating cold and moist foods, - Poor mixing of the chyle with the heat of the liver, - Or external factors like exposure to cold or dampness. As for **black bile**, the **natural kind** is the **dregs and sediment** of well-cooked blood. It is **necessary** for certain organs like **bones**, which require density and firmness. Its **final cause** includes: - Giving the blood **strength and cohesion**, - Preventing it from dissolving too quickly, - Aiding in **nourishing organs** with melancholic temperaments. The **excess or corrupt black bile**, however, forms due to **burning or rotting** processes: - It may arise from overcooked blood or other humors, - It may manifest as **bitterness**, **astringency**, or **toxic dryness**, - It collects especially in the **spleen**, which filters and retains the excess. In summary, each humor has **natural** and **unnatural** types: - The **natural** types are **functional**, arising from **moderate cooking** and **balanced temperament**. - The **unnatural** ones arise from **excess, deficiency**, or **corruption** in heat, mixing, or substance. Thus, the **humors are four**: 1. **Blood** – warm and moist; nourishes the body. 2. **Phlegm** – cold and moist; moistens and balances. 3. **Yellow bile** – hot and dry; penetrates and moves quickly. 4. **Black bile** – cold and dry; gives firmness and stability. And the **causes** of their generation are of four kinds: - **Active** (heat), - **Material** (type of food and drink), - **Formal** (quality of transformation), - **Final** (use and necessity in the body).   **The Fifth Teaching:** ## **On Temperament (Mizāj) and Equilibrium** Temperament is defined as the **quality resulting from the interaction of the four primary qualities**—heat, coldness, moisture, and dryness—when blended into a single composite entity. It is not simply the juxtaposition of these qualities, but the **resulting balance** or **domination** that emerges from their interpenetration within a substance. There are **three types** of temperaments with respect to moderation: 1. **Absolutely Balanced Temperament (al-mizāj al-mu****ʿ****tadil al-haq****ī****q****ī****)**: This is the temperament where the four qualities are blended in such equal measure that **no single quality** dominates. It is said to exist **only in the imagination**, because true equilibrium at every level is nearly impossible in the material world. 2. **Balanced in Relation (al-mizāj al-mu****ʿ****tadil bi-l-nisba)**: This is the balance **relative to a species, an organ, or a function**. For example: - The temperament of **humans** differs from that of animals. - The **heart** is warmer than the **brain**, though each may be balanced for its own function. - A **balanced temperament for digestion** may differ from that for mobility. 3. **Unbalanced or Deviation (al-mizāj al-mā****ʾ****il)**: This occurs when one or more qualities **overwhelm** the others, creating a dominant type: - If heat dominates, the temperament is **hot**. - If cold dominates, it is **cold**. - If dryness or moisture dominate, the temperament is **dry** or **moist**, respectively. Each temperament can incline toward **two qualities**: - **Hot-moist** (like blood), - **Hot-dry** (like yellow bile), - **Cold-moist** (like phlegm), - **Cold-dry** (like black bile). Thus, **eight temperaments** arise from the combinations: - Four **simple** (hot, cold, moist, dry), - Four **compound** (hot-moist, hot-dry, cold-moist, cold-dry), along with a **ninth**, which is the **balanced** temperament.   ### **Indicators and Manifestations of Temperaments** Each temperament reveals itself through **sensory signs**, **behavioral tendencies**, and **bodily reactions**. These manifestations serve as diagnostic indicators by which physicians and philosophers discern the dominant temperament in an individual or organ. 1. ##### **Hot Temperament (****ḥ****ār al-mizāj):** - **Sensory Signs**: Warm skin to the touch, a tendency to thirst frequently, preference for cold weather and foods. - **Behavioral Tendencies**: Quick movements, alert intellect, excitability, and a tendency toward anger or enthusiasm. - **Bodily Effects**: Reddening of the skin, prominence of veins, a high metabolic rate, and frequent sweating. 1. ##### **Cold Temperament (bārid al-mizāj):** - **Sensory Signs**: Cool skin, aversion to cold, frequent desire for warmth and hot foods. - **Behavioral Tendencies**: Slower movements, a calm or even sluggish demeanor, slower reaction times, and reduced energy levels. - **Bodily Effects**: Pallor, a slower pulse, cold extremities, and a tendency toward phlegm accumulation. 1. ##### **Moist Temperament (rā****ṭ****ib al-mizāj):** - **Sensory Signs**: Soft, smooth skin, often oily or damp, and a tendency to retain water or swell. - **Behavioral Tendencies**: Gentleness in demeanor, emotional pliability, forgetfulness or a dreamy disposition. - **Bodily Effects**: Increased mucus, watery discharges, and relaxed muscles. 1. ##### **Dry Temperament (yābis al-mizāj):** - **Sensory Signs**: Rough, dry skin, cracking lips, coarse hair. - **Behavioral Tendencies**: Precision in thinking and action, firmness in opinion, and a certain sharpness in speech or mood. - **Bodily Effects**: Constipation, dry cough, lean musculature, and rigidity in joints. 1. ##### **Compound Temperaments (al-amzija al-murakkaba):** These include combinations such as: - **Hot-Dry** (like yellow bile): Energetic, sharp-minded, but prone to anger and inflammation. - **Hot-Moist** (like blood): Sociable, generous, with balanced vigor but susceptible to excess heat. - **Cold-Moist** (like phlegm): Calm, patient, slow to action, but easily fatigued or congested. - **Cold-Dry** (like black bile): Reserved, introspective, precise, but prone to melancholy and stiffness. 1. ##### **Balanced Temperament (al-mizāj al-mu****ʿ****tadil):** - **Sensory Signs**: Moderate skin temperature and texture, balanced appetite, regular sleep and digestion. - **Behavioral Tendencies**: Equanimity, reasonableness, and emotional stability. - **Bodily Effects**: Healthy complexion, sound digestion, stable pulse, and harmonious organ function.   Phlegm is caused by a deficient heat (formal cause), and its material cause is a thick, moist, viscous, and cold substance derived from food. Its formal cause is incomplete digestion, and its final cause lies in its necessity and benefits, as previously mentioned. As for black bile (*sawdā**ʾ*), it has different causes: the sedimentary type arises from moderate heat, while the burnt type results from heat exceeding moderation. Its material cause is excessively thick, low-moisture substances from food, especially hot ones, which are stronger in this regard. Its formal cause is the dross that settles on one side and does not flow or dissolve. Its final cause is its necessity and the aforementioned benefits. Black bile increases due to liver heat, or due to a weak spleen, or from extreme cold that causes congealing, or from persistent congestion, or from prolonged diseases that alter the humors. When black bile accumulates and becomes trapped between the stomach and liver, the production of blood and sound humors is diminished, resulting in a deficiency of blood. You should know that heat and cold are two primary causes of the generation of humors, alongside other causes. However, moderate heat generates blood, excessive heat generates yellow bile, and extreme heat generates black bile due to intense combustion. Cold generates phlegm, and excessive cold produces black bile due to extreme congealing. Still, one must consider the receptive (passive) forces in relation to the active forces. One should not firmly believe that every temperament generates a similar humor, or that it never generates its opposite — even if not by essence, then at least incidentally — for it often happens that a temperament produces its opposite. For example, a cold-dry temperament can produce foreign moisture, not due to similarity but because of weak digestion. A person with such a temperament would be thin, with lax joints, and easily startled. --- **Chapter Nine:** ## **On the States of Purgative Medicines** Among the purgative medicines are those with severe harm, such as black hellebore, or *turbid* if it is not of good white quality but of the yellowish kind, and such as agaric if it is not pure white but tends toward blackness, and like *mazriyoun*. These substances are harmful. If it happens that one of them is ingested and harmful symptoms appear, the correct approach is to expel the drug from the body as much as possible — either by inducing vomiting or downward evacuation — and to treat with an antidote. In many cases, the harm and corruption caused by these substances can be mitigated by giving very cold water to drink and sitting in it, as with yellow *turbid* and moldy types, and also with anything that dulls the sharpness (of the medicine), such as emollients, soothing agents, and fatty substances with mucilaginous properties, which are beneficial in such cases. Also, some medicines are suitable for certain temperaments but not for others. For example, scammony does not act effectively in people from cold regions unless used in large doses, as is the custom in Turkish lands. In some places and bodies, one may need to use not the substance of the medicine but only its active power. It is also necessary to mix purgative medicines with aromatic drugs to preserve the strength of the organs, and aromatic substances are beneficial in that regard because they strengthen the vital spirit in every organ. Most of them assist through their diluting and thinning action. Sometimes, two medicines are combined — one with rapid purgative action and another with slower action. The first may complete its effect before the second even begins, or the second may be obstructed in its mixing by the first, weakening its strength. If the second starts its action afterward, it will be weak and only partially effective. Therefore, it should be combined with something that activates it quickly — like ginger with *turbid*, as it prevents it from becoming inert over time. That is why combining the two is beneficial. One must also carefully observe the foundational principles we have explained regarding the properties of purgative medicines, as we discussed in general rules concerning individual drugs. A purgative drug may work by **dissolving** (i.e., breaking down humors) along with a specific property, as is the case with *turbid*, or by **pressing out** (expressing humor) along with a property, like *chebulic myrobalan (həlīlaj)*, or by **softening**, like *shirkhaskh*, or by **lubricating**, like the mucilage of psyllium (*bazr qutūnā*) or plums. Most strong purgative drugs contain **toxicity**; they act forcibly against the natural processes, so they must be corrected with substances possessing **antidotal properties** (*fādizhariyya*). Bitterness, pungency, astringency, rot, and acidity often help the drug's action if they match the drug’s properties: bitterness and pungency aid dissolution; astringency aids pressing out; acidity helps disintegration suitable for lubrication. It is imperative not to combine a lubricant and a pressing agent in a way that their strengths are equal, but rather, one should act before the other — for example, one of the medicines should be a softener that acts first before the pressing agent comes in to purge what has already been softened. The same logic applies elsewhere. A person who is **timid, cold to the touch, with soft joints and narrow vessels** resembles the case where aging generates phlegm — for indeed, the temperament of old age is truly **cold and dry**. You must also know that **blood**, along with what flows with it through the vessels, undergoes a **third digestion**. Once it is distributed to the organs, each organ receives its **fourth digestion**. The waste of the **first digestion**, which takes place in the stomach, exits through the intestines. The waste of the **second digestion**, which occurs in the liver, is mostly expelled through urine, with the remainder exiting via the spleen and gallbladder. The waste from the **third and fourth digestions** is expelled either imperceptibly through natural dissolution, or through sweat, or through bodily filth expelled from either visible outlets like the nose and ears or invisible ones like pores, or unnaturally, like with eruptive swellings, or through body outgrowths like hair and nails. Know that **thin humors** are more difficult to evacuate, and those with **wide pores** may suffer weakening of vitality due to what follows dissolution. Thin humors are easy to purge and dissolve, and what is easily purged or dissolved can carry the **vital spirit** with it, thus diminishing it. Know also that just as these humors have causes for their **generation**, they also have causes for their **movement**. Movement and heating things cause blood and yellow bile to stir — and sometimes even black bile. Stillness, on the other hand, strengthens phlegm and types of black bile. Even **emotions** can stir the humors: for instance, blood is stirred by looking at red things, which is why people with nosebleeds are advised not to look at bright red objects.   It is also known that strong passions such as **anger** stir the **blood**, whereas **fear and worry** stir **black bile**, and **joy and relaxation** affect **yellow bile**, while **sorrow and depression** tend to generate or stir **phlegm**. These effects differ in strength and duration according to the **disposition** of the person affected and the **intensity** of the cause. Some humors may be **concentrated in specific organs**: for instance, **black bile** often resides in the **spleen**, **yellow bile** in the **gallbladder**, **phlegm** in the **stomach**, and **blood** in the **liver** and large vessels. But this concentration does not mean exclusivity — rather, it signifies predominance. All humors exist in all parts of the body to varying degrees, and the **balance** among them is crucial to health. When **any of the humors dominates**, it disturbs the balance, and this imbalance is the source of **illness**. The treatment must be aimed at restoring the proper **proportion** and **temperament** of the humors. Sometimes, this involves removing the excess humor; other times, it means altering its **quality** or **direction**. In some cases, illnesses arise not from the **quantity** of a humor, but from its **corruption** — for example, if blood becomes too hot or putrid, or phlegm becomes too cold and congealed, even if their quantities remain normal. This is why treatment must take into account not only the **amount** but also the **nature** of the humor. Thus, medical knowledge depends on understanding the **four humors**, their **natural proportions**, their **qualities** (hot, cold, wet, dry), their **places**, **motions**, and **how they respond to external and internal influences**. All of this must be assessed carefully through **observation**, **experience**, and **reasoning**, for it is the foundation of diagnosing disease and restoring health. --- **Instruction Five:** ## **One Chapter and Five Propositions on the Nature of the Organ and Its Categories** We say that organs are bodies generated from the primary mixture of the commendable humors, just as humors are bodies generated from the primary mixture of the elements. Organs are either simple or composite. The simple ones are those of which any tangible part taken is identical in name and definition with the whole—such as flesh and its parts, bone and its parts, nerve and its parts, and similar structures. These are called *homogeneous organs*. Composite ones are those of which any part taken is not identical in name or definition with the whole—such as the hand and the face. A part of the face is not a face, and a part of the hand is not a hand. These are called *instrumental organs*, for they are instruments of the soul in executing movements and functions. The first of the homogeneous organs is bone, created solid because it serves as the foundation of the body and the pillar of motion. Then comes cartilage, which is softer than bone and thus bendable, but firmer than other organs. The benefit of its creation is to facilitate the joining of bones with soft organs, so that hardness and softness do not combine directly without an intermediary, which would damage the soft parts, especially under impact or pressure. Instead, the composition is graduated, as seen in the shoulder blade and the cartilaginous extensions of the ribs at the back, and the laryngeal cartilage beneath the throat. Cartilage also facilitates the interaction of joint surfaces in motion so they are not crushed due to their hardness. Also, if some muscles extend to an organ that lacks bones to support it, such as the muscles of the eyelids, cartilage serves as a base and support for their tendons. Furthermore, cartilage is necessary in many areas as a firm support not to the extent of hardness—like in the larynx. Then come the nerves, which are brain- or spinal cord-derived substances, white in color, pliant in bending, and firm in separation. They are created to provide sensation and motion to the organs. Next are the tendons, which are substances that originate from the ends of muscles, resembling nerves. They attach to the movable organs—sometimes pulling them as the muscle contracts and bunches, drawing the organ back; and sometimes releasing them as the muscle extends and relaxes, returning it to its original or slightly extended state, depending on the length of the tendon while the muscle is in its natural position. Most often, tendons are formed from the nerve that penetrates the muscle, protruding from the opposite side. Following the tendons in this account are the ligaments—structures also of a nervous nature in texture and feel. They branch from organs toward muscles and subdivide along with the tendons into fibers. Those that remain near the muscle are filled with flesh; those that move away toward joints and the mobile organ gather into cords. These ligaments, as we mentioned, are also nerve-like structures. Some are called simply *ligaments*, while others are specifically named *sinews* (*ʿ**iqāb*). Those that extend to muscles are only called *ligaments*, while those that connect the ends of bones in a joint or between other organs and bind them firmly together are generally called ligaments, and specifically *sinews*. No ligament has sensation so that it is not harmed by the constant movement and friction it endures. The function of ligaments has already been discussed. Then come the arteries—hollow, elongated bodies that originate from the heart, of nervous and ligamentous substance, possessing expansion and contraction motions interrupted by pauses. They are created to ventilate the heart, expel smoky vapors from it, and distribute the spirit throughout the body's organs by the permission of God. Then the veins—similar to arteries but originating from the liver and immobile—distribute blood to the organs of the body. Then come the membranes—woven from imperceptible nervous fibers, thin and transverse—covering the surfaces of other bodies and enveloping them for various purposes. Among them: preserving the form and shape of the organ; suspending it from other organs and binding it through nerves and ligaments which branch into their fibers and weave them together, as in the kidney from the spine. Another purpose is to provide sensitive surfaces for otherwise insensitive organs like the lungs, liver, spleen, and kidneys. These do not have internal sensation, but they perceive external disturbances through the membranes surrounding them. If gas or swelling occurs, it is felt. Gas is sensed by the membrane's stretching; swelling is sensed by the membrane’s root and its connection to the affected organ due to heaviness. Then comes the flesh, which fills the spaces between these organs in the body and strengthens them, providing the means by which each organ maintains its inherent vital power. This power is responsible for nourishment: drawing food, retaining it, assimilating it, and expelling the waste. Then the organs differ: some also have the power to act upon other things; others do not; and the strong members push their excess toward weaker neighbors, like the heart pushes toward the armpits, the brain toward the area behind the ears, and the liver toward the groins. --- **Instruction Five ** ## **One Chapter and Five Propositions: The Nature of the Organ and Its Categories** We say that organs are bodies generated from the first mixture of the commendable humors, just as humors are bodies generated from the first mixture of the elements. Organs are either simple or composite. The simple organs are those where any sensible part you take shares in the name and definition of the whole, such as flesh and its parts, bone and its parts, nerve and its parts, and the like. These are called homogeneous organs. The composite organs are those where if you take any part, it does not share in the name or definition of the whole, such as the hand or the face. A part of the face is not a face, and a part of the hand is not a hand. These are called instrumental organs because they are the instruments of the soul in completing motions and actions. The first of the homogeneous organs is **bone**, which was created solid because it is the foundation of the body and the pillar of movement. Then comes **cartilage**, which is softer than bone and thus bends, but is harder than other organs. The benefit of its creation is that it improves the connection between bones and soft organs, so that the hard and soft do not join directly, which would injure the soft part during blows or pressure. Instead, the composition is gradual, as in the shoulder blade bone and the costal cartilages at the back of the ribs, or the cartilage under the larynx. Cartilage also allows for better joint articulation without grinding due to its hardness. Also, if some muscles extend to an organ that has no bone to support it, such as the eyelids, cartilage serves as a support and anchor for their tendons. Moreover, it is sometimes necessary to have a support in places that require strength without extreme hardness, such as the larynx. Then come the **nerves**, which are bodies that originate in the brain or spinal cord, white, pliable, and flexible in bending but firm when separated. They were created so that organs may have sensation and motion. Next are the **tendons**, which are bodies that grow from the ends of muscles, similar to nerves. They meet the moving organs and sometimes pull them by the contraction of the muscle, causing the tendon to draw back, and at other times they loosen by the relaxation of the muscle, which returns to its place or even beyond it, depending on the length of the tendon when the muscle is in its natural position. These tendons are mostly made of a nerve passing through the muscle and emerging on the opposite side. Then come the **ligaments**, which are white, solid, tendinous bands created to bind bones together at the joints and maintain the integrity of their assembly. Following that is **membrane**, which is thinner than ligament and broader. It wraps the organs and unites some of them, enclosing and protecting them from external injuries. Membranes serve to limit the expansion of organs, maintain their shape, and help retain their internal moisture. The **skin** is the outermost membrane, created to protect the underlying parts from harm. It is the wrapping of all the body, formed with sensation and coarseness proportionate to the need of each part. Next is **fat**, which is a moist, fatty substance filling the interspaces between organs to prevent friction during movement, to act as a cushion against blows, and to provide warmth and nourishment. There is also **flesh**, which is the red soft substance found in many parts of the body, especially in limbs. It is made from blood and serves to fill spaces, give shape, support movement, and enclose vessels and nerves. Also among the homogeneous organs is **blood**, which is a moist, red fluid filling the veins and arteries, and it is the food of the body. In addition, there are **humors**, which are the four types we’ve previously mentioned — each classified as either natural or unnatural. From these homogeneous organs, composite organs are made, each consisting of multiple homogeneous organs arranged in a particular manner for a specific function. Among the composite organs are some that are essential for the individual’s survival — such as the **heart**, the **brain**, and the **liver** — and some essential for the preservation of the species — such as the **testicles**. These are called **principal organs**. There are also **servant organs**, which serve the principal ones in two ways: either by preparing something they need (called *preparatory service*) or by delivering what is prepared (called *executory service*). For example, the **lungs** prepare the air for the heart, and the **arteries** deliver the blood from the heart. The **stomach** prepares food for the liver, and the **veins** carry the nourishment. Similarly, organs like the **penis** and **uterus** perform services for the testicles. Galen stated that some organs have a function only, some have a benefit only, and some have both function and benefit. For instance, the heart has only function (generating the vital spirit); the lungs have only benefit (preparing the air); and the liver has both function (producing blood) and benefit (providing nourishment). However, when we say an organ "acts," we mean it performs an intrinsic function necessary for the life of the individual or species. When we say it "benefits," we mean it serves to enable the function of another organ. We also say that some organs are formed from **semen**, especially the homogeneous ones except for flesh and fat; while others are formed from **blood**, like flesh and fat. The semen of the man and woman both contribute, as the cheese is formed from both the **rennet** and the **milk**: the rennet being the male’s semen, and the milk the female’s. Just as the rennet initiates coagulation and the milk receives it, the same applies to semen. Some believe the male’s semen contributes more to forming the **form** (ṣūra), while the female’s semen contributes more to the **matter** (mādda). Galen, however, believed both have active and passive powers — though perhaps in differing degrees. The **menstrual blood** that used to flow from the woman during her periods is repurposed to nourish the fetus. Part of it transforms into a substance similar to semen, helping form organs derived from semen. Another part becomes flesh and fat, filling in the spaces between the primary organs. Whatever remains and is not suitable for either use is expelled at birth as **lochia** (postnatal discharge). Once the child is born, its **liver** produces blood, replacing the maternal source and giving rise to the same tissues. Flesh forms from the dense component of the blood, solidified by heat and dryness. Fat, on the other hand, forms from the watery, greasy part of blood, and is congealed by cold — which is why **heat melts fat**. As for organs generated from semen, once separated or damaged, they typically do **not regenerate**, except in limited cases during **childhood**, such as bones or small veins — unlike large veins or arteries. If any part is lost, it is not replaced. However, organs that develop from blood — like **flesh** — can regenerate. And those organs formed from blood that retained **semenic power** can regrow early in life, like **teeth** in young children. But if the blood has lost that semenic quality, such regrowth no longer occurs. Sensory and motor organs may receive both capabilities from a **single nerve**, or from **separate ones**. Additionally, **all internal organs wrapped in membranes** are derived from one of the two **lining membranes**: either the thoracic or abdominal. Organs in the **chest**, like the **diaphragm**, **veins**, **arteries**, and **lungs**, derive their membranes from the lining of the ribs. Those in the **abdomen**, like the **intestines**, are wrapped in the **peritoneum**, which is the lining of the abdominal muscles. Moreover, all fleshy organs are either **fibrous**, like the muscles, or **non-fibrous**, like the liver. Movement occurs only where there are fibers. Voluntary movements arise from the **fibers of muscles**, natural movements (like in the uterus or veins) and mixed movements (like swallowing) arise from specialized fibrous arrangements — longitudinal for pulling, transverse for pushing, and oblique for holding. Organs with **one layer**, like veins, have their three types of fibers interwoven. Those with **two layers** (like the stomach and intestines) have **transverse fibers** on the outer layer and **longitudinal and oblique** ones on the inner layer, with the longitudinal fibers closer to the inner surface. This arrangement ensures that the opposing actions of **pulling** and **pushing** are not in direct conflict — essential in organs like intestines, which need both functions without resistance. Additionally, nerve-based organs that surround **foreign bodies**, like **vessels**, can be single- or double-layered. Double layers are created for several reasons: (1) to increase strength and prevent rupture from forceful movement, as in arteries; (2) to protect the stored substance — like blood or spirit — from dispersing or leaking; and (3) to assign different layers for different functions, especially when those functions rely on opposing qualities. For example, the **stomach** needs **sensation**, which comes from **nervous tissue**, and **digestion**, which comes from **fleshy tissue**. Therefore, one layer is **nervous** (for sensation) and the other is **fleshy** (for digestion), with the **inner layer** being nervous so it can detect the food it contacts, and the **outer layer** being fleshy. Furthermore, some organs are close in **temperament** to blood and are nourished easily — like **flesh** — so they do not require **storage cavities** for prolonged digestion. Others are distant in temperament and need gradual transformation to match their essence — like **bones** — which is why they are created with either **central cavities**, as in long bones (leg, arm), or **scattered cavities**, as in vertebrae. Strong organs **expel their waste** to weaker neighboring organs — for instance, the **heart** to the **armpits**, the **brain** to the area behind the **ears**, and the **liver** to the **groin**. --- **Section One:** ## **The Bones** There are thirty chapters in total. The first chapter concerns the bones and joints. We say: Among the bones are those whose relation to the body is like the foundation of a structure — such as the vertebrae of the spine, which serve as the base upon which the body is constructed, much like a ship built upon its keel. Other bones function as shields and protection, like the cranial bone (the fontanelle). Some resemble weapons used to fend off harm and impact, such as the spiny projections (sanasin) along the vertebrae of the back, resembling thorns. There are bones that serve as padding within the joints, such as the sesamoid bones found between the phalanges. Others act as attachment points for structures that require anchoring — like the hyoid bone, shaped like the letter “lam,” which supports the muscles of the larynx, the tongue, and others. In general, bones serve as structural support and uphold the body. Some bones exist solely for support and protection, and not for movement. These are solid in structure — though they do contain pores and cavities as necessary. Bones that contribute to motion are designed with a central cavity, which helps reduce their weight. The cavity is singular and located in the middle, so the bone mass remains strong and does not require dispersed food deposits that would soften it. Instead, the bone remains solid, and its nourishment — the marrow — is centralized. The cavity's presence makes the bone lighter, and having a single cavity keeps the bone denser and stronger. The solidity helps it resist fracturing during forceful movements. The marrow inside provides nourishment and moisture, preventing the bone from becoming brittle and fragmenting due to motion. Thus, the bone, though hollow, behaves as if it were solid. The cavity is reduced when strength and firmness are required, and increased when lightness is more beneficial. The spongy bones (mashāshiyya) are formed this way for nutritional reasons, and to allow the passage of substances — like inhaled aromas entering the nasal bone (cribriform plate) with air, or to receive brain waste expelled into them.   All bones are adjacent and connected; there is no significant distance between any given bone and the one next to it. In some places, there is a small gap filled by cartilage-like extensions created for the functional purposes of cartilage. Where this function is unnecessary, the joint is formed without any cartilage extension — such as in the lower jaw. The types of adjacency between bones vary: - Some bones are joined by **loose joints** (mufaṣṣal sals), - Some by **tight but non-rigid joints** (mufaṣṣal ʿasir ghayr mawthaq), - And some by **firm, interlocked joints** (mufaṣṣal mawthaq), either **inserted** (markūz), **suture-joined** (madrūz), or **adhered** (mulazzaq). - A **loose joint** is one where one of the two bones can move freely without the other moving with it — like the joint between the wrist and the forearm. - A **tight, non-rigid joint** allows only slight and difficult movement by one bone alone — such as between the wrist and the metacarpals, or between two metacarpal bones. - A **firm, interlocked joint** is one where neither bone can move independently — like the joints between the bones of the sternum. The **inserted joint** (markūz) is where one bone has a projection and the other a depression, and the projection fits securely into the depression without movement — as in teeth fixed in their sockets. The **suture joint** (madrūz) is where both bones have interlocking ridges and grooves, like a saw, and the teeth of one fit into the grooves of the other — similar to how tinsmiths join metal plates. This connection is called a **"suture"** (shāʾn or darz), found in the joints of the skull. The **adhered joint** (mulazzaq) comes in two types: - **Longitudinal adherence**, like the joint between the two bones of the forearm; - **Transverse adherence**, like the joint between the lower vertebrae of the spine, whereas the upper vertebrae are joined by non-rigid joints. --- **Chapter Two:** ### **Anatomy of the Skull (al-Qa****ḥ****f)** The function of the skull as a whole is to serve as a **shield** for the brain — protecting and covering it from harm. As for the benefit of its structure consisting of **multiple bones** rather than a single unified one, it can be considered from two perspectives: 1. In terms of the **bones themselves**; 2. In terms of what the **bones contain**. From the first perspective, there are two benefits: - First, if a specific part of the skull is afflicted with a condition like a fracture or decay, the damage does not necessarily affect the entire skull — as it would if the skull were a single bone. - Second, having multiple bones allows for the **variation in structure** required by differences in hardness, softness, porosity, density, thinness, and thickness — something not feasible if the skull were one homogenous bone. From the second perspective, the benefits concern the **features** (shu’ūn) of the skull: - Some of these features serve the **brain directly**, by allowing the escape of vapors that cannot pass through the bone due to its density. These features provide **openings for ventilation**, thereby purifying the brain. - Others allow for the **passage of nerves** originating from the brain to the various parts of the head. There are also dual-purpose features that serve both the brain and other systems: - One relates to the **blood vessels and arteries** entering the skull, providing them a path inward. - Another relates to the **dura mater** (al-ḥijāb al-thaqīl), the thick membrane covering the brain. This membrane attaches to those features so it does not rest heavily upon the brain. The **natural shape** of the skull is **rounded** for two main reasons: - Internally: A rounded shape encloses more space than other shapes of equal perimeter, maximizing the volume available to contain the brain. - Externally: A rounded surface is less prone to damage from external impacts compared to angular shapes. Additionally, the skull is not only round but **elongated**, because the origins of the cranial nerves are aligned **along its length**. This elongation also prevents compression. It includes **protrusions at the front and back** to protect the nerves that descend along the sides. There are **three true sutures** and **two false sutures** in the skull: - One of the true sutures is the **coronal suture** (aklīlī), shaped like an arch and shared with the forehead. - The second is the **sagittal suture** (sahmī), running straight along the midline from front to back. When considered in relation to the coronal suture, it is also called **sufūdī** and is shaped like an arch with a central vertical line, like this: ! - The third true suture is at the back, between the rear of the head and the base of the skull. It forms an **angled shape** and connects to the end of the sagittal suture. This is called the **lamda suture** (lāmī), as it resembles the Greek letter lambda (Λ). When these three sutures are combined, the pattern looks like this: ! The two **false sutures** run along both sides of the sagittal suture and are **parallel** to it. They do not deeply penetrate the bone and are therefore called **superficial** or **cortical** (qashriyyān). When all five sutures are present together, their configuration is as follows: !   As for the **abnormal shapes of the skull**, they are three in number: 1. **Loss of the anterior protrusion** — which leads to absence of the coronal suture at the front. 2. **Loss of the posterior protrusion** — which leads to absence of the lamda suture at the back. 3. **Loss of both protrusions** — resulting in a skull that is shaped like a sphere, equal in length and width. The esteemed physician **Galen** said: This spherical shape, due to its equal dimensions, requires proportional division of the sutures. Whereas normally there is one suture along the length and two across the width, in this shape the arrangement would be **one suture for each** — one longitudinal and one transverse, with the transverse suture crossing the width from ear to ear and the longitudinal one running through the center of the length. He added: A **fourth unnatural skull shape** — where the length is shorter than the width — is **impossible** without compromising the brain’s size or structure. This would **contradict life itself** and prevent healthy composition. Therefore, Galen affirmed the statement of **Hippocrates**, who said there are only **four skull shapes** to be known. Keep that in mind.   **Chapter Three:** ### **Anatomy of the Region Below the Skull** The head, below the skull, consists of **five bones**: four serve as **walls** and one as the **base**. These walls were made **stronger** than the fontanelle because: 1. They are more exposed to falls and impacts. 2. The need for **permeability** in the skull and fontanelle is greater due to: - The necessity of allowing vapors to pass through. - Preventing pressure on the brain. The **strongest wall** is the **posterior** one, because it is the **least protected** by sensory organs. - The **first wall** is the **frontal bone**, bounded above by the **coronal suture** and below by another suture that runs from one side of the coronal to the other, passing over the eye near the eyebrow. - The **lateral walls** on the right and left are the bones in which the ears are located, and are called the **temporal bones** due to their solidity. Each is bounded above by the **superficial suture** and below by a suture that runs from the **lamda suture** back to the **coronal suture**, with frontal and posterior boundaries accordingly. - The **fourth wall**, at the back, is bounded above by the **lamda suture**, and below by the **suture connecting the skull to the sphenoid bone**, linking the two ends of the lamda. The **base of the skull** is the bone that supports the rest — called the **sphenoid**. It is made solid for two reasons: 1. Solidity provides structural **support**. 2. A dense material is **less prone to decay**, especially since this bone lies beneath a site where waste matter regularly drains. Hence, its solidification was deliberate. Additionally, on each side of the **temples**, there are two **solid bones** covering the nerves running through the area. They are placed along the **length of the temple at a slant**, and are referred to as the **zygomatic bones** ("al-zawj").   **Chapter Four:** ### **Anatomy of the Jaws and the Nose** As for the **bones of the upper jaw and the temples**, their number becomes clear when we study the sutures of the jaw. We begin by saying: The **upper jaw** is bounded: - From above by a **suture shared with the frontal bone**, running beneath the eyebrow from one temple to the other. - From below by the **roots of the teeth**. - From the sides by a **ridge** extending from the ear region, shared with the **sphenoid bone**, which lies behind the molars. The other end curves slightly inward. Between this boundary and the **suture that cuts across the roof of the palate longitudinally**, lies the upper jaw. Within these boundaries are several **internal sutures**: - A **longitudinal suture** that cuts through the roof of the palate. - A **suture** that starts between the eyebrows and ends near the area between the two central incisors. - A suture that begins at the origin of the previous one, then curves downward toward the space between the **lateral incisor** and the **canine tooth** on the right. - Another similar suture exists on the left. Between these **three central sutures** and the lateral regions, and between the roots of the mentioned teeth, lie **two triangular bones**. But the bases of these triangles are not at the roots of the teeth. A **cutting suture** runs near the base of the nostrils, separating these bones. The three sutures extend beyond this cut to the areas already described. Beneath the **two triangles**, there are two other bones, surrounded by the **bases of the triangles**, the **roots of the teeth**, and **parts of the lateral sutures**. A separating suture runs below the middle suture, giving each bone two **right angles** at the junction, one **acute angle** near the canines, and one **obtuse angle** near the nostrils. Among the **sutures of the upper jaw**, there is one that descends from the **shared upper suture**, heading toward the eye. When it reaches the **orbit**, it splits into **three branches**: - One branch runs beneath the **shared frontal suture**, above the eye socket, and ends at the eyebrow. - A second runs below, also reaching the eyebrow but without entering the eye socket. - A third enters the socket before reaching the eyebrow. The lower these branches are (in relation to the suture beneath the eyebrow), the further they are from their upper contact point. However, the bone marked off by the **first suture** is larger than the second, and so on. As for the **nose**, its benefits are evident and **threefold**: 1. The nose helps **trap air during inhalation** by means of its cavity, allowing **a larger volume of air** to collect and be moderated before entering the brain. Although inhaled air is primarily directed toward the **lungs**, a considerable portion also travels toward the **brain**, especially during sniffing — when one is trying to identify a particular smell — since the air collects in one location in front of the **olfactory apparatus**, enabling better and more accurate perception. These are thus **three functions within one benefit**. 2. The nose assists in **articulating letters and speech**, by **modulating airflow** and preventing all the air from rushing at once into the parts of the mouth where letters are formed. This provides better control over pronunciation. This function of the **nose in regulating airflow** is similar to that of the **opening behind the larynx**, which remains unobstructed to allow passage of air for speech. 3. The nose provides **cover and protection** for the **waste material discharged from the head**, shielding it from view, and also serves as a **mechanism for expelling** that waste through blowing. The **structure of the nasal bones** consists of **two triangular bones** meeting at their upper points, with their **bases touching at an angle**, and separating below with two angles. Each bone is connected to one of the **lateral sutures** described earlier, beneath the **facial suture**. Along the lower edges of these bones are **two soft cartilages**, and between them — running down the **middle suture** — is a central cartilage that is **harder at the top** and softer at the bottom, and overall firmer than the side cartilages. - The benefit of this **central cartilage** is to **divide the nasal passage into two nostrils**, so that when excess discharge descends from the brain, it will more likely flow through **one nostril**, not blocking both inhalation passages, which are vital for drawing in air rich in spirit. - The **side cartilages** serve **three purposes**: 1. The **shared benefit of all cartilages** attached to bone endings, which has already been covered. 2. To allow the nostrils to **expand if needed**, to improve inhalation or blowing. 3. To assist in **dislodging vapor** during exhalation through their shaking and trembling motion. The bones of the **nose are made thin and light**, because **lightness** is more needed here than **strength**, especially since they are not connected to organs susceptible to afflictions and are **placed where they are easily perceived by the senses**. As for the **lower jaw**, it consists of **two bones** that are **joined beneath the chin** by a **firm joint**. Each of the other two ends widens outward and then curves inward, forming a **hooked extension** that connects to a **matching projection** from the bone where it ends. They are **bound together** by ligaments, with one bone fitting atop the other.   **Chapter Five:** ### **Anatomy of the Teeth** The total number of **teeth** is **thirty-two**, though in some people, the **molars** (also called "wisdom teeth") may be absent. These are the **four rearmost teeth**, so in such cases, the number is **twenty-eight**. Among the teeth: - There are **two central incisors** and **two lateral incisors** in the **upper jaw**, and the same in the **lower jaw** — their function is **cutting**. - There are **two canines** in the upper jaw and **two** in the lower — their function is **tearing**. - Then there are the **molars** for **grinding**, usually **four or five** on each side, in both upper and lower jaws. Thus, the total becomes **thirty-two or twenty-eight** teeth. The **molars** usually **emerge** in the **middle period of growth**, i.e., **after puberty and before full maturity**, which typically occurs around the **age of thirty**. For this reason, they are sometimes called the **“teeth of maturity”** or **“wisdom teeth.”** Each tooth has: - A **root** embedded in a **socket** within the jawbone. - A **crown** exposed outward with a **sharp edge**. Surrounding each socket is a **rounded bony growth** that **encases the tooth and holds it firm**. There are also **strong ligaments** securing the teeth. Except for the molars, **each tooth generally has a single crown**. As for the **molars embedded in the lower jaw**, they typically have **at least two roots**, and often — especially the **rearmost molars** — **three**. The **molars in the upper jaw** generally have **at least three roots**, and the farthest molars may have **four**. The **roots** of the molars are numerous because: - These teeth are **larger**, - They **perform more work**, - And the **upper molars** need additional support because they are **suspended** rather than grounded. Gravity causes a **tendency to pull them away from the root direction**, whereas the **lower molars**, being anchored by weight, do not face the same opposition. Among all the bones, **none possesses sensation** except the **teeth**. **Galen** said: "Experience proves that the teeth possess sensation, aided by a force that reaches them from the **brain**, allowing them to discern **heat and cold**."   **Chapter Six:** ### **The Spine** The **spine** was created for **four primary purposes**: 1. **As a channel for the spinal cord**, which is essential for sustaining life, as we will elaborate in the section specifically devoted to the spinal cord. Here, we provide a brief overview: - If **all the nerves** were to originate from the **brain**, the **head** would need to be **far larger** than it currently is, which would make it too heavy for the body to support. - Additionally, the nerves would have to **travel great distances** to reach the body’s extremities, making them vulnerable to **injury or disconnection**. - Their **length** would also **weaken their ability** to transmit motion to the limbs. - Hence, the **Creator**, exalted be His name, wisely extended a portion of the **brain downward** into the body — this is the **spinal cord** — like a **channel flowing from a spring**, from which the **nerves are distributed** to the various parts of the body according to proximity and need. - The **spine** thus serves as a **protected conduit** for this cord. 2. The spine serves as a **protective shield** for the **noble organs** situated in front of it. For this reason, it was designed with **spines (protrusions)** and **processes** for added defense. 3. The spine acts as the **central structural support** for the entire skeletal system — much like the **central beam** around which a ship is constructed. The spine is first **set in place**, and then the **rest of the bones are attached to it**, which is why it was made **particularly strong and firm**. 4. The spine provides the **human being with upright posture, stability, and balance**, allowing for coordinated movement in all directions. - It was therefore constructed not as **one solid bone**, nor as **many scattered small bones**, but as a series of **well-organized vertebrae**. - The **joints** between these vertebrae are not **too loose** (which would weaken the structure), nor are they **too rigid** (which would restrict flexibility).   **Chapter Seven:** ### **Anatomy of the Vertebrae** The **vertebra** is a **bone** that contains, at its center, a **hole** through which the **spinal cord** passes. Each vertebra may have **four protrusions (processes)** — two on the right and left sides, located beside the central opening. - The **upper pair** of protrusions point **upward** and are called **ascending processes**. - The **lower pair** point **downward** and are referred to as **descending or inverted processes**. Sometimes, a vertebra has **six protrusions**: - **Four on the sides**, as mentioned above, - And **two more**, typically positioned **to the rear**, serving as anchor points for ligaments and muscles.   Sometimes, the vertebra has **six processes** in total: - **Four lateral processes** (two on each side), and - **Two additional ones** — one **in front** and one **behind**, or sometimes **both behind**, depending on the vertebra's position and function. Each vertebra is joined to the one above and below it through **articulations** and **ligaments** that allow for **flexibility** while maintaining **strength and protection**. The opening in the center of the vertebrae — through which the spinal cord runs — forms a **continuous canal** when the vertebrae are stacked together. The **processes** also serve as **attachment points** for muscles and ligaments, which help control the **motion** and **stability** of the spine. The **shape** of each vertebra may vary depending on: - Its **location** (cervical, thoracic, lumbar, sacral), - The **load it bears**, - And the **range of motion** required in that part of the spine. --- ### **Vertebral Structures and Functions** Sometimes the vertebrae have **eight processes**, and the benefit of these processes is that they allow for **articulated connections** between vertebrae: - Some are joined by **notches**, and others by **rounded, socket-like heads**. Certain processes are not created for articulation but rather serve the purpose of **protection, shielding**, and **resistance** against external impact. These are also **anchoring points** for ligaments. These processes are **broad, firm bones** laid out along the vertebral column. - The processes that project **rearward** are called **spines** or **spinous processes**. - Those that extend to the **right and left** are called **wings** or **transverse processes**. Their protective role is especially crucial for shielding what lies **deeper within the torso** — including **nerves, veins, and muscles**. Some of these wing-like processes, especially those **adjacent to the ribs**, have a particular function: they contain **depressions** in which the **rounded heads of the ribs** are lodged and held in place. Each wing has **two depressions**, and each rib has **two protrusions** that fit into these depressions. Among the wings are some that have **two heads**, making them appear like **double wings** — this is particularly true in the **cervical vertebrae**, and we will explain the reason for this later. The vertebrae, besides the **main central opening** for the spinal cord, also have **additional openings (foramina)** through which **nerves exit** and **vessels enter**. Some of these openings are located **entirely within a single vertebra**, while others are formed **jointly** between two adjacent vertebrae: - These joint openings lie at the **shared boundary** between them. - Sometimes, the opening lies **between the upper and lower edges** of two vertebrae. - At times, it may be formed from **half-circles** in each vertebra, either equal in size or with one half larger than the other. These foramina were **not placed at the rear**, since that would leave them **exposed to injury** and **lack proper protection**. Nor were they placed at the **front**, for that is where the **weight of the body naturally leans**, both due to **gravity** and **intentional motion**. Placing them there would: - Weaken the structure, - Make the joints harder to secure tightly, - And expose the **emerging nerves** to compression and damage. Thus, these foramina were placed **to the sides**, where they would be **safely nestled between structural supports**. The **protective processes** are also often surrounded by **ligaments and tendons**, and a **slimy moisture** runs over them to ensure that **friction does not harm the flesh** through contact. The **articulating processes** likewise are **firmly bound** to one another by **multiple ligaments** from all directions — especially from the **front**, which is made more secure than the **rear**. Why? Because the body **requires more forward bending** than backward arching. Hence, the **ligaments at the back** are intentionally made **looser**, and the **space behind** is often filled with **moist, viscous tissues** to **protect and cushion** the area. As a result of this design: - The **spinal vertebrae** are so **tightly interlocked** from one side that they resemble a **single unified bone** made for **stability and stillness**. - But from the other side, they remain **flexible**, like **multiple bones**, allowing **movement and adaptability**. --- **Chapter Eight:** ### **The Benefit of the Neck and the Anatomy of Its Bones** The **neck** was created to serve the **trachea** (windpipe), and the trachea was created to serve functions that we will explain later in its proper place. Since the **cervical vertebrae** — and the upper part of the spine in general — are **supported by what lies beneath them**, they necessarily had to be **smaller**. That’s because: - The **carried structure** must be **lighter** than the **carrier**, in order for movement to remain balanced and coordinated according to the laws of proper function. Furthermore, because the **upper end of the spinal cord** must be **thicker and larger**, like the **source of a river**, since it gives rise to **more nerve branches**, the **foramina (openings)** in the cervical vertebrae had to be **wider**. But this combination of **small vertebrae** and **wide openings** results in **thinner bones**, and so something had to compensate for this structural delicacy — hence, the cervical vertebrae were made of **tougher, denser material** than others. Because the **body of each cervical vertebra** is **thin**, their **spines (posterior projections)** were also made **small** — otherwise, the vertebrae would be prone to **fracture or injury** when impacted by strong external forces. And since the **spines** were kept small, the **transverse processes (wings)** were made **larger**, often with **two heads**, giving them a **doubled** structure. Also, the **neck** requires **more motion** than **stability**, since reducing the number of cervical vertebrae does not significantly lighten the load on the rest of the spine. For this reason, the **joints** between the cervical vertebrae were made **looser** and **more flexible** than those below them. Yet, what the cervical spine lacks in **firm interlocking**, it **regains** — and even **surpasses** — through the **network of nerves, muscles, and veins** that **surround and reinforce** it. This makes up for the **reduced stiffness** of the joints. Each of the **seven cervical vertebrae** (except for the **first**) has all **eleven processes** we previously described: - A **spinous process** (spine), - Two **transverse processes** (wings), - Four **articulating processes** pointing upward, - And four pointing downward. Each **wing** is split into **two branches**, and the **nerve opening** is shared between each pair of vertebrae, divided equally between them. However, the **first and second cervical vertebrae** have **special characteristics** that set them apart. First, the **side-to-side (lateral)** movement of the head is accomplished through the **joint between the skull and the first cervical vertebra**, while the **forward-and-backward** movement is achieved through the **joint between the skull and the second vertebra**. Let us start with the **first joint**: On each of the **upward projections** of the **first vertebra**, there is a **depression** into which **projections from the skull** fit. When one skull projection **rises** and the other **sinks**, the head **tilts toward the side** with the sunken part. As for the **second joint**, it could not be placed on the **first vertebra**, so a **second vertebra** was created specifically for that purpose. From its **forward, inner-facing side**, a **long, solid projection** (called the **dens**, or "tooth") emerges and fits through an opening in the first vertebra, in front of the spinal cord. This **opening** is **shared** between the two vertebrae. It extends **from back to front**, and is **longer** than the opening that extends **side to side**, because in the front-to-back direction, there are **two projections** that must pass through. As for the **width** of the opening, it corresponds to the **larger** of the two projections. This **dens (or "tooth")** is what allows the **head to rotate forward and backward**: - It rises from the **second vertebra**, - Inserts into a **groove** in the base of the skull, - And the **groove wraps around it**, allowing for **pivoting motion**. This **tooth-like projection (dens)** was made to extend **forward** for two key reasons: 1. To be **more securely protected**. 2. So that the **thinner part** of the first vertebra would be **on the inside**, not exposed outward. The **first cervical vertebra** has **no spinous process**, for several important reasons: - To avoid **excessive weight**, - To prevent it from being **easily injured** (since any large projection could become a weak point), - And to avoid compressing the **many nerves and muscles** that surround this region. Additionally, a **protective spine** was **not needed here**, because this vertebra is already **deeply embedded** and **shielded** by surrounding structures, making it **less prone to trauma**. For the same reasons, this vertebra also lacks **transverse processes (wings)** — especially since most of the **nerves and muscles** are **tightly packed** beside it. There simply wasn’t space for wings. Another unique feature of the **first vertebra** is that its **nerve exits** do **not emerge from the sides**, nor from a **shared opening**, but rather through **two distinct openings**, located **just behind and slightly above** on each side. Why? Because if the nerves exited in the region where the **skull projections interlock** with the vertebra, the **movement** of these projections would **seriously damage the nerves**. Nor could the nerve exit be placed in the **socket of the second vertebra**, where two of its projections insert into grooves in the third vertebra — as this joint also involves **strong movement**. And placing the nerve exit **in the front or back** was also not possible: - The **front** is occupied by the dens, - And the **back** is too exposed to compressive forces. Likewise, placing the opening **on the sides** is problematic due to the **thinness of the bone**, since the dens leaves little room. Thus, the only viable option was to place the **two small foramina** slightly **behind and between the sides and rear**, which necessarily meant that the **nerves passing through them had to be very fine**. As for the **second cervical vertebra**, the **nerve** could not emerge from the **top**, as it did in the first, because doing so would **risk crushing it** due to the **movement of the first vertebra** — especially when the head **bends forward or backward**. Nor could the exit be located at the **front or back**, for reasons already explained, nor on the **sides**, because: - That would force the **second vertebra to share the opening with the first**, - And the **nerve root** would have to be **too thin**, unable to make up for any shortcoming in the first vertebra. This would result in **weakened and unstable nerve pairs**, emerging together from the junction of the first and second vertebrae. And we’ve already shown why the **first vertebra** could not have its nerve exits on the sides. Therefore, the **nerve exit** in the **second vertebra** was placed **on either side of its spinous process**, where it aligns with the **nerve openings of the first vertebra**, and where the **bone mass of the first vertebra** could safely contribute to their formation. The **dens (tooth-like process)** of the second vertebra is **firmly joined** to the first with **strong ligaments**. The **joint between the head and the first vertebra**, and the joint between the **first and second vertebrae**, are **more flexible** than any other vertebral joints — and for good reason: these joints must support a wide range of **essential head movements**. In practice, when the head moves in **any direction** with one joint, the second vertebra moves with the other, functioning almost like a **single unit** with its pair: - When the head moves **forward or backward**, the second vertebra acts as one with the first. - When the head moves **side to side**, without any twisting, the **first and second vertebrae move together** like a single bone. The **thoracic vertebrae** are those that **connect to the ribs** and enclose the **organs of respiration**. There are **eleven vertebrae** with **spinous processes** and **transverse processes**, and **one vertebra without transverse processes**, making a total of **twelve thoracic vertebrae**. Their **spinous processes** are **uneven** in size: - The vertebrae that support the **most important organs** are **larger and stronger**. - The **transverse processes** of the thoracic vertebrae are **more robust** than those of other regions because of their **direct connection to the ribs**. The **upper seven thoracic vertebrae** have **large spinous processes** and **thick transverse processes**, providing **strong protection** for the **heart**. Because their bodies are large to support this function, their **articulating processes** (those forming joints) are **short and wide**. Among the **first ten thoracic vertebrae**: - The **upward-pointing articulating processes** contain **grooves** to receive the matching **downward-pointing projections** of the vertebra above, - And their **spinous processes** slope **downward**. The **tenth vertebra**, however, has a **different structure**: - Its **spinous process is upright and dome-shaped**, - And its **articulating processes** on both sides have **grooves**, but **no projections** — it receives projections **from above and below**. Below the tenth, in the **lower thoracic vertebrae**: - The **projections point upward**, - And the **grooves are on the bottom**, reversing the pattern of the upper vertebrae. - Their **spinous processes** curve **upward**. The **twelfth vertebra** has **no transverse processes**, because the **last rib** it connects to is **shorter** and less in need of support. However, its structure still includes **additional reinforcements** to make up for the missing wing-like projections. This unique design meets **two goals**: 1. **Protection**, especially of the **diaphragm**, which attaches to the twelfth vertebra. 2. **Stability**, ensuring that this vertebra can bear the **transition to the lumbar region** without structural weakness. The **upper thoracic vertebrae** (above the twelfth) are **broad enough** to eliminate the need for **extra articulating processes**; instead, their **large spinous and transverse processes** occupy the available bone structure. Finally, because the **thoracic vertebrae** are larger than the **cervical vertebrae**, the **shared nerve openings** between vertebrae could not remain evenly split. Instead: - The **upper vertebra** contributes slightly **more** to the shared opening, - And the **lower one** contributes slightly **less**, - Until, by the **tenth vertebra**, each vertebra **fully contains** its own nerve opening. In the **lumbar** and **sacral vertebrae**, the vertebral bodies are large enough to **fully contain** the **entire foramen (nerve opening)**. --- **Chapter Ten:** ### **Anatomy of the Lumbar Vertebrae** The **lumbar vertebrae** have **spinous processes** and **broad transverse processes**. Their **lower articulating projections** (those that face downward) are wide and resemble **protective wings**. There are **five lumbar vertebrae**. The **lumbar region**, along with the **sacrum**, serves as the **foundation** or **base** for the entire spine. It supports: - The **weight of the torso**, - The **bones of the pelvis**, especially the **pubic bone**, - And functions as the **origin point** for the **nerves of the legs**. --- **Chapter Eleven:** ### **Anatomy of the Sacrum** The **sacrum** consists of **three fused vertebrae**. It has: - The **most interlocked joints**, - The **strongest articulations**, - And the **widest transverse processes**. The **nerve openings** in the sacrum are **not positioned exactly on its sides**, to avoid being compressed by the **hip joint**. Instead, they are located: - **Slightly medially**, toward the **inside**, - And **slightly anterior and posterior** to accommodate for positioning. Structurally, the **sacrum** closely resembles the **lumbar vertebrae** in both **strength** and **design**. --- **Chapter Twelve:** ### **Anatomy of the Coccyx** The **coccyx** (tailbone) is composed of **three cartilaginous vertebrae** with: - **No transverse or spinous processes**. Nerves emerge from it through **shared foramina (openings)**, similar to the arrangement in the **cervical region** due to the small size of the bones. The **third coccygeal vertebra** has a **single nerve** that exits from its **terminal point**. **Chapter Thirteen:** ### **General Reflection on the Function of the Spine** We have spoken in detail about the bones of the spine; now let us offer a **comprehensive statement** about the spine as a **single, unified structure**. The **entire spinal column** is formed as **one continuous unit**, distinguished by the **most advantageous of shapes** — the **circular form**. This shape is the **least vulnerable** to damage from **external collisions** and shocks. For this reason: - The **upper vertebrae** curve downward, - The **lower vertebrae** curve upward, - And both arcs **converge at the middle** — the **tenth vertebra** — which acts as the **central point** of balance. This **middle vertebra** (tenth) is the **center of the spinal curves**, not in terms of **number**, but in terms of **length and shape**. Since the spine must sometimes **bend or twist sideways**, this movement is made possible by the **shifting of the middle**: - When the center moves to one side, the upper and lower parts of the spine follow, - This causes both ends of the spine to **tilt toward each other**. To allow for this type of flexibility, the vertebrae were **not formed with locking projections**, but instead with **grooves**. Meanwhile, the **upper and lower vertebrae** were shaped so that: - The **upper edge** slopes **downward**, - And the **lower edge** slopes **upward**. This slanted design: - Facilitates the **lateral shift** of the spine, - Allows the **upper vertebrae** to be pulled **downward**, - And allows the **lower vertebrae** to rise **upward**.   **Chapter Fourteen:** ### **Anatomy of the Ribs** The **ribs** serve as a **protective barrier** for: - The **respiratory organs** (like the lungs), - And the **upper digestive organs**. They were **not made as a single solid bone**, in order to: - **Avoid excess weight**, - Prevent **total loss of function** in the event of damage, - And allow **greater expansion** when the body needs more air (as during deep inhalation or digestive swelling). The **spaces between the ribs** are filled with **chest muscles** that assist in **breathing and related functions**. Since the **chest cavity** encloses the lungs, heart, and their associated organs, it was essential to provide **strong protection**. Despite this, **comprehensive reinforcement** of the chest from all directions would **not restrict these organs**, nor harm them — so: - The **first seven ribs** on each side fully **encircle the upper chest**, - They meet at the **sternum (breastbone)**, - And **completely enclose the heart**, the **primary organ**, from all sides. The **lower ribs**, which cover the **digestive organs**, are designed differently: - They resemble **hooks from behind**, - Are not joined at the front, - And **gradually shorten and taper** from top to bottom. This tapering allows for: - Protection of internal organs like the **liver** and **spleen**, - While also allowing **room for the stomach** to expand during digestion or bloating, - Preventing **compression** of the abdominal area. Thus: - The **upper seven ribs** are called the **true ribs** (or "ribs of the chest"), - There are **seven on each side**, - The **middle ones** are the **longest**, - The **top and bottom ones** are **shorter**. This **arch-shaped configuration** offers better **coverage and containment**. Each rib: - First **curves downward**, - Then bends **upward again** toward the front, - Where it connects with the **sternum**, as we’ll explain shortly. At the back: - Each rib has **two rounded projections** that fit into **two depressions** in the **transverse processes** of the thoracic vertebrae, - This forms a **double joint** with the vertebrae. The **upper seven ribs** also articulate with the **sternum**. The **lower five ribs**, shorter and tapering: - Are referred to as the **false ribs**, - They are connected at the back, - But at the front, they link through **cartilage**. This **cartilaginous connection** prevents: - **Fracture** during impact, - And **injury to soft organs** like the **diaphragm** and others. These lower ribs meet the **soft tissues** via an **intermediate structure** that balances firmness and flexibility.   **Chapter Fifteen:** ### **Anatomy of the Sternum** The **sternum** is composed of **seven bones**. It was **not created as a single bone** for the same reasons noted in other parts of the body: - To maximize **functional benefit**, - And to allow **greater flexibility** in **assisting the movements** of nearby respiratory organs during **expansion** and **contraction**. Therefore, the sternum was made: - **Porous and light**, - **Joined by cartilage** to support its **subtle motion** during breathing — even though its joints are **securely bound**. It consists of **seven segments**, matching the number of **ribs** attached to it. At its **lower end**, the sternum connects to a **broad cartilaginous bone** whose bottom is **rounded** — this piece is called the **xiphoid process** (“al-khanjari” in Arabic) due to its **dagger-like shape**. This xiphoid process serves two key functions: 1. **Protecting the opening of the stomach** (gastric orifice), 2. **Mediating the transition** between **rigid** (bone) and **soft** (internal organs) structures — a principle we’ve referred to repeatedly in other sections.   **Chapter Sixteen:** ### **Anatomy of the Clavicle** The **clavicle** is a bone placed on **each side** of the **upper sternum**. Its design: - **Arches outward** at the base of the neck, forming a **gap** (fujrah) that allows: - **Blood vessels** to pass upward toward the brain, - And **nerves** to pass downward from the brain. Then, the clavicle: - **Curves laterally**, extending outward toward the **outer side** of the body, - And **connects to the head of the shoulder blade** (scapula), - Where it forms a joint that: - **Secures the shoulder**, - And, together with the scapula, **supports the upper arm** (humerus).   **Chapter Seventeen:** ### **Anatomy of the Shoulder Blade** The **shoulder blade** (al-katif) was created with **two primary purposes**: 1. **To suspend the upper arm (humerus) and the hand**: - Without the shoulder blade, the arm would be **fused to the chest**, - This would restrict **independent motion** between the two arms, - And limit their **range and ease of movement**. - Therefore, the scapula was made **detached** from the ribs and chest, - With **expanded areas** allowing for **wide-ranging mobility**. 2. **To serve as a protective shield** for the vital organs inside the chest: - It **replaces the function** of the spinal **spines** and **transverse processes** in areas where no vertebrae exist to absorb shock, - And where **no sensory organs** exist to feel pain from such impact. Structurally: - The **outer edge** of the scapula is **thinner**, - While the **inner edge** is **thicker**, - This results in a **shallow socket** at its outer end, - Into which fits the **rounded head of the humerus** (upper arm bone), - Allowing for a **wide arc of motion** in the shoulder joint. **Summary review:** - **Chapter 14**: The ribs — their structure, variation, and protective and respiratory functions. - **Chapter 15**: The sternum — its segmented design and role in breathing and organ protection. - **Chapter 16**: The clavicle — its function as a bridge and passageway for vessels and nerves. - **Chapter 17**: The shoulder blade — its dual purpose in arm mobility and thoracic protection. --- **Chapter Eighteen:** ### **Anatomy of the Shoulder and Upper Arm** The shoulder blade has two **bony protrusions**: 1. The first extends **upward and backward**, known as the **acromion** or "the raven’s beak." - It connects to the **clavicle (collarbone)** through a **ligament**, forming the **shoulder joint**. - It prevents the **dislocation of the humerus (upper arm bone)** upwards. 2. The second protrudes **inward and downward**, - It also helps prevent the **head of the humerus** from dislocating. As the blade extends medially (inward), it flattens and widens to provide more **protective coverage**. On its surface is a **triangular-shaped projection**, with: - Its **base** facing outward (lateral), - And its **angle** pointing inward (medial), So that the **contour of the back remains smooth**; If the base were medial, the **skin would protrude**, causing pain upon impact. This projection acts like the **spinal processes** of vertebrae and is designed for **protection**, and is called the **"spine of the scapula."** At the outer edge of the shoulder blade is a **cartilage** that forms a **rounded socket** — this connects to the **head of the humerus**.   **Chapter Eighteen (continued):** ### **Anatomy of the Humerus** The **humerus** was created as a **cylindrical (rounded) bone** to: - Make it **less prone** to fractures and injuries. Its **upper end** is **convex** (bulging), - It fits into the **socket of the scapula** through a **loose and not overly tight joint**. This looseness causes the joint to be more susceptible to **dislocation**, but it offers **two key advantages**: 1. **Functional necessity** — allowing smooth, multi-directional motion. 2. **Safety** — although the arm needs to move in many directions, - Most of the time, the **humerus remains stationary** while the **rest of the arm moves**. - Thus, its joint does **not experience as much wear and tear**, - And is **less in need of reinforcement** compared to the other joints of the arm. The **shoulder joint** is supported by **four ligaments**: 1. A **membranous ligament** that surrounds the joint — like those found in other joints. 2. Two ligaments descending from the **acromion**: - One is **transverse**, wrapping around the **head of the humerus**. - The second is **larger and stronger**, and it descends along with: 3. A **fourth ligament** from a nearby projection, both of which are embedded in a **groove**. These ligaments are shaped **transversely**, especially where they **contact the humerus**, - Their role is to **secure** the humerus and to **connect with the muscles** that surround it internally. The **shaft of the humerus**: - Is **concave medially (toward the body)** and **convex laterally (away from the body)**, - This allows muscles, nerves, and vessels to attach securely, - It also improves **the way one arm wraps around the other** and supports **armpit movement**.   **Chapter Eighteen:** ### **The Lower End of the Humerus and the Elbow Joint** The **lower end of the humerus** features **two adjacent protrusions**: - The **inner one** (facing inward) is **longer and more slender**. - It does **not form a joint** with any bone; - Instead, it serves to **protect nerves and blood vessels**. - The **outer one** (facing outward) is involved in forming the **elbow joint**, - It contains a **rounded knob** (condyle) that we’ll describe in more detail later. Between these two protrusions is a **groove**, and on each side of that groove are **two notches**: 1. The **upper, inner notch** is **smooth and flat**, with no ridge or separation — - It functions as a **sliding surface**. 2. The **outer notch** is **larger**, and its part that is adjacent to the inner notch is: - Not smooth, - Not rounded like a cavity, - But rather **shaped like a vertical wall**. This shape allows the **ulnar process** (the projection at the back of the forearm) to: - **Engage precisely with the humerus** during outward movement, - And **lock into place**, preventing the arm from overextending. The physician **Hippocrates** referred to these two notches as the "**eyes**" of the elbow.   **Chapter Nineteen:** ### **Anatomy of the Forearm** The **forearm** is composed of **two parallel bones**, both extending lengthwise. These are collectively known as the **ulnae**. - The **upper bone**, on the **thumb side**, is **thinner** and is called the **upper ulna** (i.e., **radius**). - The **lower bone**, on the **little finger side**, is **thicker**, as it bears more weight, and is called the **lower ulna** (i.e., **ulna**). Each bone has a distinct functional role: - The **radius** enables the **forearm to rotate** and **twist outward** (pronation and supination). - The **ulna** enables the **forearm to flex and extend** (bend and straighten). The **middle sections** of both bones are **slimmer**, - Because they are surrounded and protected by **thick muscles**, - And do **not require extra bulk** for structural strength. In contrast, their **ends are thicker**, - To allow for **stronger ligament attachment**, - As they are exposed to **frequent stress, impact, and motion**, - Especially at the joints, which lack muscle and flesh cover. The **radius** is slightly **curved**, - Originating from the **medial side** (closer to the body) and bending slightly outward (laterally), - This curvature **facilitates rotational motion**. The **ulna** is **straight**, - As this structure is better suited for **flexion and extension**.   **Chapter Twenty:** ### **Anatomy of the Elbow Joint** The **elbow joint** is formed by the articulation of: - The **upper end of the radius** (the upper ulna), - The **upper end of the ulna** (the lower ulna), - With the **lower end of the humerus**. The **upper end of the radius** has a **well-shaped socket**, - Into which fits the **condyle (rounded knob)** of the **lateral side** of the humerus. - When the radius rotates within this socket, - It produces the motion of **supination and pronation** (twisting of the forearm). As for the **ulna**, it has **two protrusions** at its upper end, - With a **groove between them**, shaped like the **Greek letter sigma (Σ)**. This groove is: - **Convex on the surface**, - Its underside is **concave**, - So that it fits perfectly into the **groove on the humerus**, which is also **concave**, - But its shape is like the **curve of a circle**. The **elbow joint is completed** when: - The groove between the **ulnar processes** fits into the **groove on the humerus**. When this **groove moves backward and downward**, - The **arm straightens** (extension). - But when the groove hits the **bony barrier** in the socket (the one that holds the condyle), - It **blocks further extension**, - And stops the **arm and forearm** in a **fully extended position**. When the groove **slides forward and upward**, - The **arm flexes** (bends), - Until the **forearm touches the upper arm** from the **medial and front sides**.   **Chapter Twenty-One:** ### **Anatomy of the Wrist** The **wrist (carpus)** is composed of **many small bones**, - So that **if one bone is injured**, the rest can still function — minimizing total disability. There are **seven primary carpal bones**, arranged in **two rows**, plus **one additional bone**. **The Seven Main Wrist Bones:** - **First row (closer to the forearm):** - Contains **three bones**. - Since this row is adjacent to the forearm, the bones are **slender and refined**. - **Second row (closer to the metacarpals and fingers):** - Contains **four bones**. - As this row connects to the metacarpals and fingers, the bones are **broader**. The three bones of the first row: - Have **thinner ends** on the side facing the forearm, - With **tighter connections and finer articulations**. Their ends facing the second row: - Are **broader**, - With **looser joints and less refined articulation**. **The Eighth Bone:** - Not part of either row. - It was created to **protect a nerve** that passes toward the **palm**. The **triangular configuration** of the first row: - Creates a **pointed end**, - Which fits into the **socket** located at the ends of the radius and ulna (forearm bones), - Forming the **wrist joint** responsible for **flexion and extension**. The **extra bone** in the lower ulna: - Fits into a **socket** in the nearby wrist bones, - Forming a **secondary joint** responsible for **rotation and pronation/supination**.   **Chapter Twenty-Two:** ### **Anatomy of the Metacarpus (Palm)** The **metacarpus**, or the palm of the hand, is also composed of **multiple bones**, - So that a single injury does not render the entire hand useless, - And to allow the palm to **cup inward** when **grasping rounded objects**, - As well as to **control the flow of liquids** held within it. These bones are **tightly bound together**, - To prevent them from **spreading apart**, - Which would weaken the palm’s ability to **grip** and **contain** what it holds. If one were to **peel away the skin** of the palm, - One would find these bones so **firmly connected** - That their **joints are almost imperceptible** to the touch. Nevertheless, - They are joined by **ligaments** that **secure them tightly** to one another, - While still allowing a **slight degree of flexibility**, - So the palm can **concave slightly** during gripping. There are **four metacarpal bones**, - Because they connect to the **four fingers**. They are: - **Closely positioned** on the side that connects to the **wrist**, - To ensure **firm attachment** to the compact wrist bones. - And **slightly spread apart** toward the **fingers**, - To connect smoothly to the **more widely spaced finger bones**. The **inner sides** of these bones are **concave**, - To aid in **gripping** and conforming to the **shape of held objects**. The **joints between the metacarpals and the wrist** - Are formed by **sockets** in the ends of the wrist bones, - Into which fit the **heads** of the metacarpals, - Covered in **cartilage** for smooth articulation.   **Chapter Twenty-Three:** ### **Anatomy of the Fingers** The **fingers** are tools that assist in **grasping objects**. They were not created as **flesh alone**, without bones — even though it is technically possible for movement to occur in flesh-only limbs, as seen in certain **worms** and **fish** — because such motion would be **weak** and **unreliable**, like that of people with tremors. Nor were the fingers created from **a single bone**, as that would have made their movements **cumbersome**, like those experienced by people with **fused or rigid limbs**. Instead, the fingers are each made of **three bones**, because: - Adding more bones might slightly **increase flexibility**, - But would **reduce strength and stability**, - Which are essential for precise grasping. - Reducing the number of bones to two would **increase strength**, - But **limit the range of motion**, - Which is necessary for their intended function. The **bases of the finger bones** are **wider**, - While their **tips are narrower**. - The **lowest (proximal)** phalanges are the **largest**, - And the size **gradually decreases** toward the **fingertips**. This shape ensures a **proper proportion** between what **supports** and what is **supported**. The finger bones are **cylindrical and round**, - To help **resist injuries**. They are **solid**, without cavities or marrow, - To increase their **strength** during movements like **gripping** or **pulling**. The bones are **concave on the inner side** and **convex on the outer**, - So they can **better grasp**, - And apply pressure when **touching or manipulating objects**. They are **not shaped with dips or bulges at their joints**, - To ensure the whole finger acts as **a unified structure** during use. However, the **outermost fingers** — the **thumb and little finger** — - Have **convex surfaces** on the sides that face **away from other fingers**, - So that when all five fingers are **brought together**, - They **form a circular shape**, - Which protects the hand and improves function. The **inner surfaces** of the fingers are **fleshy**, - To provide **support** and allow compression when gripping. - The **outer surfaces** are not as fleshy, - So they don’t become overly heavy, - And the whole hand remains an effective **instrument of force**. The **flesh of the fingertips** is abundant, - To provide **good cushioning** and ensure **tight, seamless contact** when pressing on objects. Finger lengths are arranged so that: - The **middle finger** is the longest, - Then the **ring finger**, - Followed by the **index**, - And finally the **little finger**. This arrangement allows the **tips of all four fingers** to align evenly when the **hand is closed**, - Leaving **no gaps** — perfect for gripping **round objects** with both the fingers and the palm. The **thumb** balances the function of the **four fingers**. If the thumb were placed elsewhere — - Like in the **center of the palm**, - We would lose many functions associated with the palm. - Or if it were placed **next to the little finger**, - The two hands could not **face each other** effectively for **grasping**. - Worse still, if it were located **behind the palm** and **not connected to the metacarpals**, - The distance between it and the other fingers would be too great. By placing the thumb **on the opposite side** of the four fingers, - The hand can **surround** large objects more effectively. The thumb also functions like a **clamp**, - While the **ring finger and little finger** act as a **bottom cover** or **support**. The **joints of the fingers** are connected by **interlocking edges and sockets**, - Held together with **strong ligaments**, - Covered with **cartilage membranes**. The **gaps between joints** are filled with **tiny bones** called **sesamoid bones**, - To increase **stability** and improve joint function.   **Chapter Twenty-Four:** ### **The Function of the Fingernails** The **fingernail** was created for **four distinct purposes**: 1. **To support the fingertip** — So that the fingertip **does not weaken** when applying **pressure** or **gripping** something. 2. **To aid in picking up small objects** — Without the nail’s edge, it would be **difficult to grasp** fine or delicate things. 3. **To assist in cleaning and scratching** — Making it possible to **remove debris**, **relieve itching**, or perform **fine tactile tasks**. 4. **To serve as a weapon in certain situations** — This function is **more relevant for animals**, While the first three are **especially useful for humans**. The nail was created to be: - **Rounded at the tip**, to suit its functions. - Made of **firm material**, but with **a degree of flexibility**, - So that it can **yield under impact** and **not shatter easily**. It is also **constantly regenerating**, - Because it is subject to **frequent wear**, **friction**, and **trimming**.   **Chapter Twenty-Five:** ### **Anatomy of the Bones of the Pubic Region** Near the **sacrum**, there are **two bones**, one on the right and one on the left, - Connected at the **center** by a **firm joint**. These two bones serve as the **foundation** for all the bones above them - And act as **carriers and transmitters** of the weight from the **upper to the lower** body. Each of these bones is **divided into four parts**: 1. The part **facing outward**, toward the **lateral side**, - Is called the **ilium** or **hip bone** (*ḥ**arqufa* or *ʿ**a**ẓ**m al-khāṣira*). 2. The part that faces **forward** - Is called the **pubic bone** (*ʿ**a**ẓ**m al-**ʿ**ā**na*). 3. The part **toward the back** - Is called the **ischium** or **hip bone** (*ʿ**a**ẓ**m al-wark*). 4. The **lowest and innermost** part - Is called the **acetabulum** (*ḥ**aqq al-fakhidh*), - Because it contains the **concavity** into which fits the **rounded head of the femur**. This region houses several **important organs**, including: - The **bladder**, - The **uterus** (in females), - The **seminal vessels** (in males), - The **rectum**, and - The **anus**.   **Chapter Twenty-Six:** ### **A General Account of the Function of the Leg** The function of the **leg** lies in **two main roles**: 1. **Stability and posture** — This is achieved through the **foot**, which provides **firm support** for the body. 2. **Movement and locomotion** — This includes **walking**, **climbing**, and **descending**, And is performed by the **thigh** and **shin** (lower leg). If the **foot** is afflicted by any impairment, - Then **standing upright and remaining balanced** becomes **difficult**, - Although **movement** is still possible — but only to the extent that one leg can compensate with **extra stability**. Conversely, if the **muscles of the thigh and lower leg** are affected, - Then **balance** may still be possible, - But **movement** and **locomotion** become **difficult or impaired**.   **Chapter Twenty-Seven:** ### **Anatomy of the Femur (Thigh Bone)** The **first bone** of the leg is the **femur**, - And it is the **largest bone** in the body, - Because it **bears the weight** of all that is above it - And **transfers it** to the parts below. The **upper end** of the femur is **rounded**, - So that it may fit into the **acetabulum** (hip socket) of the pelvis. It is **convex on the outer (lateral) side**, - And **concave inward and toward the back**, - For if it were positioned in a **straight and aligned** fashion with the socket, - It would result in a condition resembling **bow-leggedness**, - As seen in individuals with that **natural deformity**. Moreover, such a configuration would: - Fail to **protect the major muscles**, **nerves**, and **blood vessels** in the area, - Prevent the **body as a whole** from assuming a proper shape, - And make **sitting posture** ineffective. Also, if the femur were **not angled inward**, - It would produce another form of **bow-leggedness**, - Which would impair **balance**, - And prevent the body from achieving a **straight and upright posture**. At its **lower end**, the femur has **two protrusions (condyles)** - That serve the **knee joint**. Let us now turn to the anatomy of the **shin (sāq)**, - Followed by the **knee joint**.   **Chapter Twenty-Eight:** ### **Anatomy of the Shin** The **shin**, like the **forearm**, is composed of **two bones**: 1. The **larger and longer** one, on the **inner side**, - Is called the **greater tibia** (*al-qaṣaba al-kubrā*). - It is the **main bone** of the shin. 2. The **smaller and shorter** one - Does **not reach the femur**, ending **short of it**, - But it extends to the **same lower level** as the tibia, - And is called the **lesser tibia** (*al-qaṣaba al-ṣughrā*). The shin is: - **Curved outward (laterally)** in its upper part, - Then **curved inward (medially)** at its lower end, - So that it aids **upright balance** and **stability**. The **greater tibia**, which is the **true shin bone**, - Was created **smaller** than the **femur**, - Because it must serve **two opposing functions**: 1. To provide **stability** and **support** — a reason to make it **larger**. 2. To allow for **ease of motion** — a reason to make it **lighter and smaller**. Since the **latter purpose** (movement) is more **crucial** for the shin, - It was made **smaller**, - Whereas the **femur**, where stability is more essential, was made **larger**. The shin was given a **moderate size**, - For if it were any **thicker**, movement would be impaired, - As seen in cases of **elephantiasis** or **varicose disorders**. - If it were any **thinner**, it would lack strength, - Making it **unable to support** the body above — - As in individuals born with **slender shins**. Despite this, the shin is **supported and reinforced** - By the **lesser tibia**, which adds to its strength. The **lesser tibia** also has **other functions**, such as: - **Protecting nerves and blood vessels** that run between the two bones, - And **sharing** in the **ankle joint**, - To strengthen and stabilize the **flexion-extension mechanism**.   **Chapter Twenty-Nine:** ### **Anatomy of the Knee Joint** The **knee joint** is formed by the insertion of the **two projections** - Located at the **lower end of the femur**, - Into a corresponding **socket**. The joint is **reinforced** by: - A **spiraling ligament**, - A **deep-seated stabilizing ligament**, - And **two strong lateral ligaments**, one on each side. The **front of the joint** is covered by the **kneecap** (*al-ra**ḍ**fa*), - Which is a **rounded bone**, somewhat circular in shape. Its function is to: - **Resist pressure** and protect the joint during **kneeling** and **sitting postures**, - **Prevent dislocation or rupture** under strain, - And **support the movement** of the joint when **transferring body weight**. Its **placement at the front** of the knee is intentional, - Because the **greatest pressure** and risk of injury - Happens at the **front** during **bending**, **rising**, and similar motions. The joint does not experience **violent flexion** to the **back**, - And only experiences **limited motion** to the sides, - But it does undergo **strong forward bending**, - Making its **forward protection** especially important.   **Chapter Thirty:** ### **Anatomy of the Foot** The **foot** was created to serve as an **instrument of stability**. Its shape was designed to be **elongated forward**, - In order to assist in **upright posture** by providing a **forward anchor point**. It was given an **arch** (ʾakhmaṣ) along its **inner side**, - So that the foot **tilts slightly inward** during walking, - Which helps **counterbalance** the weight placed on the **supporting leg** during motion, - Thereby **maintaining bodily equilibrium**. This design also allows the foot to: - **Step on irregular surfaces**, such as **uneven ground or rocky paths**, - Without causing severe pain, - And to **grip** or **conform** to inclined surfaces, like **steps or slopes**. The foot is composed of **many bones**, each with **specific functions**, including: - **Enhanced grip**, - **Better surface adaptation**, - And **resistance to injury**. The foot can **grasp** the ground, much like the **hand** grasps an object. When made of **multiple parts**, the foot can **adjust its shape** to maximize grip. This is **superior** to a foot made of a **single solid piece**, - Which could not easily conform to different shapes. There are also **general benefits** shared by all **multi-boned structures**. The foot consists of **26 bones**, including: 1. The **heel bone (ka****ʿ****b)** — Completes the **joint** with the **lower leg**. 2. The **calcaneus (‘aqib)** — Provides the **primary support** for standing. 3. The **navicular bone (zawraqī)** — Forms the **arch of the foot**. 4. **Four tarsal bones**, - Which connect the **midfoot** to the **metatarsals**. 5. One **cuboid bone (nirdī)** — Shaped like a **hexagon**, - Positioned on the **outer side**, - It helps anchor that side of the foot to the ground. 6. **Five metatarsal bones** — That lead to the **toes**. Among these, the **heel bone (ka****ʿ****b)** in humans is more **box-shaped** than in animals, - Because it is the **most noble bone** of the foot when it comes to **movement**. Likewise, the **calcaneus (‘aqib)** is the **most noble bone** for **stability**. The heel bone sits **between the two projections** of the tibia bones, - And is **enclosed by them** from above and behind, - And from both sides — the **inner (medial)** and **outer (lateral)**. Its two ends fit into the **calcaneus**, locking in like **pegs** into sockets.   **Chapter Thirty-One:** ### **Anatomy of the Toes** The **toes** are instruments that assist in **grasping** and **holding onto things**. They were not created as **fleshy masses devoid of bones**, Even though **movement** would still have been technically possible — As is the case with **some worms** and **fish**, which have limited, weak movement. But that would have made the toes' **functions feeble and ineffective**, Much like the hands of people who suffer from **tremors**. Nor were the toes created from **a single bone**, Because such a design would make their **movements stiff and awkward**, As seen in those afflicted with **spasms** or **rigid muscles**. Instead, the toes were composed of **three bones each**, Because if the number were **increased**, Though that would add more movement, It would **inevitably** lead to **weakness** and **loss of control** — Especially where **firm grip and precise action** are required. Likewise, if made of only **two bones**, That would indeed increase their **rigidity**, But it would **greatly limit** the necessary range of movement, Which is **more essential** in the toes than excess strength. The bones of the toes are: - **Wider at their base** and **narrower at the tip**, - With the **lowest bones** (closest to the foot) being **larger**, - Progressively **decreasing in size** until the **tips of the toes** (the phalanges), - This is done to ensure the **proper ratio between the supporting part and the movable part**. Their bones are **rounded** to **protect against injury**. They were made **solid**, lacking cavities or marrow, To give them **greater durability** and **resistance during motion, grasping, and pulling**. The inner surface is **concave**, the outer is **convex**, - To better **grip** what the toes grasp, - And to **massage or apply pressure** to whatever they sense or encounter. The joints between them were not designed with their own **distinct curvatures or shapes**, So that they might connect more closely, forming **a single coherent unit**, - Especially when needed to perform functions of **a single strong bone**. Yet the **outermost digits**, like the **thumb** and **little finger**, Have curvatures on their side that does **not face another toe**, So that when all five toes **come together**, They form a nearly **circular arrangement**, - Which **protects them from injury**. The **inner surfaces** of the toes were made **fleshy**, - To **support and cushion** them during contact, - While the **outer surfaces** were kept **lean**, - So the toes wouldn't be heavy or blunt instruments. The **flesh at the tips** of the toes was made more **pronounced**, - To allow better **alignment** and **smooth contact** when the toes come together. The **middle finger** is the **longest**, followed by the **ring finger**, Then the **index finger**, and finally the **little finger** — This order ensures the tips all **align evenly** during grasping, Without leaving **gaps**, while allowing the fingers and palm to **curve around circular objects**. The **thumb** is the **counterpart** to all four fingers. If it were placed elsewhere, it would lose its **function**: - If placed in the **center of the palm**, - We would lose most of the palm’s functions. - If placed near the **little finger**, - The hands would no longer **face one another**, - And couldn't **grip together** effectively. Even worse, if placed **behind the hand**, - It would no longer be a useful counterforce to the other fingers, - And if it were not **connected to the metacarpal**, - The distance between it and the rest of the hand would be too great. But when the **four fingers** wrap around something from one side, And the **thumb presses from the other**, The palm can **enclose large objects** effectively. The **thumb** also acts like a **clamp** over whatever the palm holds and hides. While the **little finger and ring finger** form the **base and support** underneath. The bones of the fingers are joined with **interlocking notches and ridges**, - Covered by **viscous fluid**, - Reinforced by **strong ligaments**, - Coated in **cartilaginous membranes**, - And filled with small **sesamoid bones** for added strength.   **Chapter Thirty-Two:** ### **The Function of the Fingernail** The **nail** was created for **four purposes**: 1. To act as a **support for the fingertip** (al-anmula), - Preventing it from **collapsing or weakening** when applying pressure to something. 2. To enable the **finger to grasp small objects** with precision. 3. To allow the finger to be used in **cleaning or scratching** when needed. 4. To serve as a **natural weapon** in certain cases. The **first three functions** are more relevant to **humans**, While the **fourth** is more pertinent to **other animals**. The **nail** was created with a **rounded edge**, for well-known functional reasons. It was made of a **pliable, bone-like substance**, - So that it could **compress under contact** without breaking. It was also designed to **grow continuously**, - Since it is frequently **subjected to wear, friction, and erosion**.   **Chapter Thirty-Three:** ### **Anatomy of the Pubic Bones** At the level of the **sacrum (al-****ʿ****ajz)** are **two bones**, - One on the **right** and one on the **left**, - Joined at the center by a **strong joint**. These bones serve as the **foundation** for all the **upper bones** and as **bearers and transmitters** of the **lower bones**. Each of these two bones is divided into **four parts**: 1. The part facing the **lateral side** is called the **ilium** (*al-**ḥ**urqafa*), also known as the **hip bone** (*ʿ**a**ẓ**m al-khāṣira*). 2. The part that faces **forward** is called the **pubic bone** (*ʿ**a**ẓ**m al-**ʿ**ā**na*). 3. The part facing **backward** is called the **ischium** (*ʿ**a**ẓ**m al-warak*). 4. The part facing **downward and medially** is called the **acetabulum** (*ḥ**aqq al-fakhidh*), - This is the **concavity** into which the **rounded head of the femur** fits. Upon this bone are placed several **important organs**, including: - The **bladder** (*al-mathāna*), - The **womb** (*al-ra**ḥ**im*), - The **semen-conveying vessels** in males, - The **anus** (*al-maq**ʿ**ada*), - And the **perineum** (*al-sarm*).   **Chapter Thirty-Four:** ### **A General Statement on the Function of the Leg** The overall function of the **leg** pertains to **two main purposes**: 1. **Support and posture** — This is fulfilled primarily by the **foot**, which provides **stability** and **balance**. 2. **Movement**, both **forward** and **backward**, as well as **upward** and **downward** — This is accomplished through the **thigh (fakhidh)** and **shin (sāq)**. If the **foot** is afflicted by any **ailment**, - It becomes difficult to maintain **balance and posture**, - Though **movement** may still be possible to some degree — Depending on the **extra support** one leg provides when the other is compromised. However, if the **muscles of the thigh or shin** are afflicted, - Then **posture** remains relatively unaffected, - But **movement** becomes significantly hindered or impossible.   **Chapter Thirty-Five:** ### **Anatomy of the Femur** The **femur** is the **first bone** of the leg and the **largest bone in the body**, - Because it **bears the upper body** and **transmits force downward**. Its **upper end** is **rounded and domed** - So that it fits snugly into the **hip socket (****ḥ****aqq al-fakhidh)**. - This head is **convex on the outer side** and **concave on the inner side and rear**, - Because if the bone were placed in a straight line or aligned directly with the socket, - It would cause an **outward bowing** of the legs, - As seen in people with **natural curvature (fahaj)** of the limbs. - This would also hinder the **protection** of the **large muscles, nerves, and veins** in the region. Furthermore: - A straight alignment would produce **rigid posture** and impede **comfortable sitting**. - If not inclined **inward**, another kind of bowing would occur, - Undermining **upright stance** and **even weight distribution**, - Leading to **imbalance**. At its **lower end**, the femur has **two protrusions** designed for forming the **knee joint**. We will now discuss the **shin (sāq)**, followed by the **knee joint**. --- **Chapter Thirty-Six:** ## **The Shin** The **shin**, like the **forearm**, is composed of **two bones**: 1. The **larger and longer inner bone**, known as the **tibia** (*al-qaṣaba al-kubrā*). 2. The **smaller and shorter outer bone**, known as the **fibula** (*al-qaṣaba al-ṣughrā*). - This bone does **not reach the femur**, but **ends short of it**, - Although at the **lower end**, it reaches the same level as the tibia. The **shin** curves **outward (toward the lateral side)** at first, - Then curves **inward** at its lower end, - In order to promote **upright posture** and **balance**. The **tibia**, being the **true shinbone**, - Is **smaller** than the femur. - This is because two conflicting design requirements converge in it: - On the one hand, it must be **large** to provide **support and stability** for the body above. - On the other hand, it must be **lightweight** to allow for **mobility**. Since the second purpose (**mobility**) is **more critical** in the shin, - It was made **smaller**. In contrast, the **femur** was made **larger**, - Because its primary purpose is **bearing weight**. Thus, the **shin** was given a **moderate size** — - If it were made larger, **movement would be hindered**, as seen in people with **elephantiasis** or **varicose veins**. - If it were made smaller, it would result in **weakness**, **reduced mobility**, and **inability to bear weight**, - As seen in those with **naturally thin legs**. Despite this, the shin is still **reinforced and strengthened** by the **fibula**, - Which also serves other functions: - **Shielding nerves and veins** running between the two bones. - And **sharing in forming the ankle joint**, - To **strengthen and stabilize** the **joint for flexion and extension**.   **Chapter Thirty-Seven:** ### **The Knee Joint** The **knee joint** is formed by the **entry of the two protrusions** at the lower end of the **femur** - Into the appropriate **depressions** on the **tibia**. - These are **secured** by: - A **spiral ligament**, - A **deep-binding ligament**, - And **two strong lateral ligaments** on either side. The **front of the joint** is covered by the **kneecap (al-ra****ḍ****fa)** — - Which is the **visible eye of the knee**, - A **somewhat circular bone**. The **function** of this kneecap includes: - **Protecting the joint** from damage during kneeling, sitting, and crouching. - **Reinforcing the joint**, which bears the body’s weight during movement. Its **position** is oriented **forward**, - Because **most of the stress** and **forceful bending** occurs in that direction. - The knee does not bend **forcefully backward**, - And only **slightly to the sides**, - Whereas it **frequently bends forward**, - Such as during **standing up, kneeling**, and similar actions.   **Chapter Thirty-Eight:** ### **Anatomy of the Foot** The **foot** was created as a **tool for stability** and **balance**. Its **elongated shape**, extending **forward**, helps the body **stand upright** by distributing weight over a longer base. It was formed with a **medial arch (al-akhmaṣ)** — the side **toward the inner leg** — - So that the **inclination of the foot** during walking supports **upright posture**, - Especially when **weight-bearing** occurs on the **opposite leg**, - Ensuring that the **balance of the body** remains steady. Additionally: - This design allows for **stepping on uneven terrain** without severe discomfort, - And improves the foot’s ability to **grip uneven surfaces** such as **stairs or inclined paths**. The **foot** was composed of **many bones** — - A design that offers multiple **benefits**, including: - **Enhanced grip**, like a **hand holding onto the ground**, - And the ability for its parts to **move independently**, - Making **foot function** more efficient than if it were a **single rigid block**. The **foot** contains **26 bones**, divided as follows: 1. **The Talus (al-ka****ʿ****b)** – - Completes the **joint with the shin** (sāq). 2. **The Heel Bone (al-****ʿ****aqib)** – - The **main pillar** of foot stability. 3. **The Navicular Bone (al-zawraqī)** – - Forms the **foot arch**. 4. **Four tarsal bones (****ʿ****i****ẓ****ām al-rusgh)** – - Connect to the **metatarsals**. - One of them is **polygonal like a die (nardy)**, - Positioned on the **outer side** to **support lateral stability** on the ground. 5. **Five metatarsal bones (****ʿ****i****ẓ****ām al-mas****ḥṭ****)** – - Form the **main framework** of the foot. Among these: - The **human talus** is **more cube-like** than in animals, - Making it **the most dignified of the foot bones**, - In terms of its role in **movement**. - The **heel bone** is the **most dignified** among the leg bones, - In terms of its role in **support**. The **talus** is situated between the **two protrusions** of the shin bones, - Which **enclose it** from above, behind, and on both sides. Its **ends insert into depressions in the heel bone**, - In a **peg-like fashion**. **Chapter Thirty-Nine:** ### **Anatomy of the Hip Bones** At the level of the **sacrum (****ʿ****ajz)**, there are **two bones** — one on the right and one on the left — - Which are **joined in the middle** by a **firm joint**. - These two bones serve as the **foundation** for: - All the **upper bones** of the body, - And the **carrier and connector** for the bones **below**. Each of these hip bones is **divided into four parts**: 1. The part that lies **laterally** is called the **ilium (al-****ḥ****urqafa)** or **hip bone**. 2. The part that lies **anteriorly** is called the **pubis (****ʿ****a****ẓ****m al-****ʿ****ā****na)**. 3. The part that lies **posteriorly** is called the **ischium (****ʿ****a****ẓ****m al-wirk)**. 4. The part that lies **inferiorly and medially** is called the **acetabulum (****ḥ****aqq al-fakhidh)**, - Because it contains the **concavity** that receives the **rounded head of the femur**. This bone supports **important organs**, such as: - The **urinary bladder**, - The **uterus**, - The **spermatic vessels** in males, - The **rectum (al-muq****ʿ****ada)**, - And the **anus (al-sarm)**.   **Chapter Forty:** ### **General Purpose of the Leg** The **benefit of the leg** lies in **two main functions**: 1. **Stability and support (al-thabāt wa-l-qiwām)** – This is primarily achieved through the **foot**. 2. **Movement in various directions** — – Whether **horizontal**, **upward**, or **downward** — – And this is made possible by the **thigh and shin**. If the **foot** is afflicted by an ailment, - The person finds **standing and balance difficult**, - But can still manage **movement**, - Albeit only to the extent permitted by the **extra support** from the **other leg**. On the other hand, - If the **thigh and shin muscles** are afflicted, - Then **standing becomes easier**, - But **movement** becomes **difficult**.   **Chapter Forty-One:** ### **Anatomy of the Femur** The **first bone of the leg** is the **femur**, and it is the **largest bone in the body**. This is because it both: - **Carries** everything above it, - And **transmits weight** to everything below. Its **upper end is domed**, - So it can **fit securely** into the **socket of the hip (****ḥ****aqq al-wirk)**. - This head is **convex laterally**, - But **concave medially and posteriorly**. This angulation is **intentional**. - Had it been placed in a straight line with the **acetabulum**, - It would have resulted in a **type of bowleggedness**, - Similar to those with congenital deformities. Moreover, it would have: - **Failed to protect** the **large muscles**, nerves, and vessels in the region, - **Prevented straight posture**, - And made **sitting awkward**. If it had not been inclined medially, - A different kind of **bowleg** would have occurred, - Causing poor posture and misalignment. At its **lower end**, the femur has **two protrusions**, - Designed for **articulation with the knee**. But before addressing that, we will next examine the **tibia (al-sāq)**.   **Chapter Forty-Two:** ### **Anatomy of the Shin** The **shin**, like the forearm, is composed of **two bones**: 1. The **larger and longer one** is the **medial bone**, known as the **greater tibia (al-qaṣaba al-kubrā)**. 2. The **smaller and shorter one** is the **lateral bone**, known as the **lesser tibia (al-qaṣaba al-ṣughrā)**. - This lesser tibia **does not reach the femur** but stops short of it. - However, its **lower end** reaches the **same level** as the greater tibia. The shin also exhibits: - A **lateral convexity**, - And at its **lower end**, a **medial convexity**, - Both of which are designed to **improve balance and upright posture**. The **greater tibia** — which is the **true shinbone** — - Was made **smaller than the femur**, because it needed to strike a **balance**: - It required **size and strength** to provide **stability and support**, - But also **lightness** for **agile movement**. Since **agility** is more essential to the shin’s purpose, - It was designed to be **lighter and smaller**. The **femur**, needing **strength and bearing capacity**, was made **larger**. The shin was thus given a **moderate size** — - If it were **too large**, it would impede movement (as seen in **elephantiasis** or **varicose veins**), - If it were **too small**, it would lack strength and struggle to **support the body’s weight**, - As seen in people with **very thin shins**. Despite this, the shin is **strengthened** and **supported** by the **lesser tibia**, - Which also serves to: - **Protect the nerves and vessels** that run between the bones, - And **participate** with the greater tibia in forming the **ankle joint**, - Enhancing its **flexion and extension**. **Chapter Forty-Three:** ### **Anatomy of the Knee Joint** The **knee joint** is formed by the insertion of the **two projections** at the lower end of the **femur**. These projections are **secured** by: - A **twisting ligament** that wraps around them, - A **deep-set tensioning ligament**, - And **two strong lateral ligaments** — one on each side. The **front** of these projections is reinforced by the **patella (al-ra****ḍ****fa)**, which is the **knee cap**. - This is a **rounded bone**, shaped **somewhat circularly**. Its **purpose** is to: - **Resist impact** and prevent **dislocation** during actions like **kneeling** or **sitting back on the heels**, - **Reinforce the joint**, which bears the **weight of the body** during **movement**. It is placed at the **front of the joint**, - Because most of the **forceful bending** occurs **forward**, - There is **rarely any intense backward bending**. As for **lateral movement**, - The bending is **minimal**, - So the joint is primarily designed to **bend forward**, - Where it endures **the greatest pressure**, especially during **rising** and **kneeling**.   **Chapter Forty-Four:** ### **Anatomy of the Foot** The **foot** was created as an **instrument for balance and stability**. Its shape is **elongated forward**, - To assist with **upright posture** when the body leans upon it. It has a **medial arch** on the inner side, - So that during walking, the **foot inclines inward** toward the **opposite leg**, - Which improves **balance**, especially when one leg is **bearing weight**. This design: - Helps absorb the **force** of **stepping on uneven terrain**, - Reduces **pain**, - And allows the foot to **grip** surfaces like **stairs** and **slopes**. The **foot** is made of **numerous bones**, which serves several functions: 1. It allows for **grip and clasping** of uneven ground, - Just as the **hand** grasps objects. 2. It ensures the foot can **adapt its shape** for better grip, - Unlike a single solid piece, which cannot change form. 3. It brings the **general advantage** of **having multiple bones**, - Which allows for **flexibility**, **shock absorption**, and **durability**. There are **twenty-six bones** in the human foot: 1. The **talus (ka****ʿ****b)** — - Forms the main **ankle joint** with the **shin**. 2. The **calcaneus (****ʿ****aqib)** — - Provides the **main support for standing**. 3. The **navicular (zawraqī)** — - Supports the **arch of the foot**. 4. Four **tarsal bones** — - Connect the rearfoot to the **metatarsals**. 5. One **cuboid (nirdī)** — - Located on the **lateral side**, - Its hexagonal shape stabilizes the **outer edge** of the foot. 6. Five **metatarsal bones** — - Extend toward the **toes**. The **human talus** is **more cuboidal** than in other animals, - Making it **better suited for upright walking**. The **calcaneus**, meanwhile, is the **most important bone** for **support and posture**. The **talus** is positioned between the **lateral and medial malleoli** of the tibia, - Enclosed from all sides — top, back, lateral, and medial — - With its ends **inserting into sockets** in the **calcaneus**, - Much like a **peg fitting into a hole**. --- ## **Structure of the Ankle, Heel, and Foot Bones** The **ankle bone (al-ka****ʿ****b)** serves as the **intermediary between the shin and the heel**. Through it, these two bones are firmly connected, forming a **stable joint** that prevents **dislocation or instability**. It is, in truth, **positioned centrally**, although due to the **medial arch of the foot (al-akhmaṣ)**, it may appear to be slightly shifted toward the **outer side (al-wa****ḥ****shī)**. The ankle connects to the **navicular bone (al-****ʿ****a****ẓ****m al-zawraqī)** in the front. - This navicular bone, in turn: - Connects **posteriorly to the heel (al-****ʿ****aqib)**, - **Anteriorly** to **three of the tarsal bones**, - And **laterally** to the **cuboid bone (al-****ʿ****a****ẓ****m al-nard)**. The **cuboid** can be counted either as a **separate bone** or as the **fourth** among the **tarsal bones**. The **heel bone** is positioned **beneath the ankle**. - It is **solid and rounded toward the back** to withstand **shocks and injuries**, - And **smooth on its underside** to provide **flat contact** with the ground and enhance **foot placement during standing**. Its **dimensions and density** were created in proportion to the bones it supports, allowing it to **bear the body’s weight** independently. - It is **triangular in shape** to facilitate **extension**, - And tapers slightly as it reaches the **arch (al-akhmaṣ)** and **lateral side**, - Allowing for a **gradual concavity** in the arch, extending from the rear toward the center of the foot.   ### **Foot Bones and Their Functions** The **tarsal bones (****ʿ****i****ẓ****ām al-rusgh)** differ from those in the **wrist (kaff)** in that they are arranged in **a single row**, whereas the wrist bones are arranged in **two rows**. - Additionally, the **number of bones in the foot is significantly fewer**. This distinction serves a functional purpose: - The **hand** requires **greater movement and grasping ability**, hence the need for more and more flexible bones. - The **foot**, however, is primarily designed for **stability**, not grasping, so a simpler, more solid structure suffices. Having **too many components and joints** in the foot would be detrimental to its **grip and firmness**, due to the **excessive looseness and separation** that would result. - Conversely, having **no looseness at all** would prevent **moderate flexibility**, which is essential. Therefore, it is better for **grasping** functions to have **more and smaller parts**, - But for **weight-bearing**, fewer and **larger components** are preferable. The **metatarsus (musht al-qadam)** consists of **five bones**, - Each connecting to **one of the five toes**, which are arranged in **a single straight row**. This is because: - The need for **firmness and stability** in the toes **outweighs the need for grasping**, which is the primary function in the **fingers** of the hand. Each toe — except the **big toe (al-ibham)** — consists of **three phalanges (salāmiyyāt)**. - The **big toe** has only **two**. Thus, we have now explained the structure of the **bones** sufficiently. In total, when counted, the **bones of the human body** amount to **248**, - Not including the **sesamoid bones (al-samsamāniyyāt)** or the **bone shaped like the Greek letter lambda (lā)**. --- **Second Division:** ## **The Muscles** **Chapter One: On Nerves, Muscles, Tendons, and Ligaments** Voluntary movement occurs in the limbs through a **force that flows from the brain** via the **nerves**. However, **nerves are not well-suited** to connect directly to **bones**, which are the **true foundations** of the limbs involved in voluntary movement. - This is because **bones are hard**, while **nerves are delicate**. Out of divine wisdom, the Creator caused to **emerge from the bones** something **resembling nerves**, known as **tendons (****ʿ****uqab)** and **ligaments (rubā****ṭ****)**. - These are then **joined** and **interwoven** with the nerves as **a single unit**. Because the **composite structure** of nerve and ligament is always **very fine**, - And because the **nerve’s thickness** cannot remain consistent from its **origin to its terminal branches**, - Especially as it **branches out** and spreads within the body, The portion of the nerve reaching any single bone becomes **much thinner** than at its source. If the nerve alone were responsible for **moving a limb**, - It would become too delicate and prone to **deficiency** as it spread further from the brain or spinal cord. Therefore, the Creator, in His wisdom, enhanced it by: - **Expanding** the structure formed by the nerve and ligament, - **Filling its gaps** with **flesh**, - **Covering it** with a **membrane (ghishā****ʾ****)**, - And placing a **central axis (like a shaft or pivot)** made of **nerve matter** at its core. Thus, the resulting structure is a **composite organ**, made of: - The **nerve**, - The **tendon**, - The **fibers (al-līf)**, - The **fleshy padding**, - And the **covering membrane**. This organ is what is called the **muscle (****ʿ****a****ḍ****ala)**. - When it **contracts**, it **pulls the tendon**, - Which is itself composed of ligament and nerve, - And draws the limb **toward the muscle**. - When it **relaxes**, the tendon loosens, and the **limb moves away**.   **Chapter Two:** ### **On the Muscles of the Face** It is known that the **facial muscles** correspond to the **moving parts** of the face. These include: - The **forehead**, - The **eyeballs**, - The **upper eyelids**, - The **cheeks**, - The **lips** (both independently and in coordination), - And the **corners of the mouth**.   **Chapter Three:** ### **On the Muscles of the Forehead** The **forehead** moves by means of a **thin, transverse, membranous muscle**. - This muscle **spreads beneath the skin** of the forehead and is so closely **interwoven** with it that it **becomes almost part of the skin’s substance**, - Making it difficult to peel away. This muscle moves the **overlying skin** without the need for a **tendon**, - Since the skin it acts upon is **broad and light**, and such structures are **not well-suited to tendon-driven movement**. - When this muscle **contracts**, it **raises the eyebrows**. - When it **relaxes**, it helps the **eyelids** close. **Chapter Four: On the Muscles of the Eyeball (Miqla)** The muscles that move the **eyeball** are **six in total**: 1. **Four muscles** at the **four sides** — upper, lower, inner (nasal side), and outer (temporal side). - Each of these moves the eye **in its respective direction**. 2. **Two additional muscles** allow for **circular motion (tawrīb)** — i.e., rotation. Behind the eyeball lies a **supporting muscle** that: - **Holds the optic nerve**, - Provides **stability**, - **Prevents bulging**, - And maintains the eye’s alignment during **focused vision**. Due to the complex **branching of the fibrous sheaths** surrounding this supporting muscle, - Some anatomists considered it **a single muscle**, - Others considered it **multiple muscles**.   **Chapter Five:** ### **On the Muscles of the Eyelid** The **lower eyelid** does not require independent movement, - Since the **goal of blinking** is achieved **by moving only the upper eyelid**. The Creator, in His wisdom, minimized the **number of anatomical structures** wherever possible, - Since **too many parts** increase the **risk of dysfunction**. Although it would have been **possible** to make the **lower lid movable** instead, - The preference was for the structure **closest to the nerve origin**, - And the **upper lid** is **closer to the origin of the facial nerve**. Moreover: - The **upper lid** must perform **two actions**: - **Rising** during eye opening, - And **descending** during blinking. - Since blinking requires **a muscle that pulls downward**, the nerve must approach it **at an angle**, - Moving **from the top and side**, either toward the **middle** or **edge** of the eyelid. If it reached the **middle**, the **upper part of the iris would be covered** when the lid raised. If it reached only one **edge**, the closure would be **uneven** — tight on one side and loose on the other. Thus: - **Two muscles** were created, - Originating from the **inner and outer corners (al-mawqayn)**, - To **evenly draw** the eyelid **downward** from both sides. As for **lifting** the eyelid: - It requires only **one muscle**, - Positioned in the **middle**, - Whose tendon **spreads along the edge** of the eyelid. - When this muscle **contracts**, the eyelid **opens**. This muscle **descends vertically**, - Lies **between two membranes**, - And connects to a **cartilage-like structure** underneath the lash line.   **Chapter Six:** ### **On the Muscles of the Cheek** The **cheek** has **two types of movement**: 1. One that **follows the motion of the lower jaw**, 2. And another in **coordination with the lips**. - The motion caused **by the jaw** results from the **jaw muscles**. - The motion **shared with the lips** is caused by **muscles of the cheek itself**, jointly serving both. Each cheek has **a single broad muscle**, commonly known by name. - Each of these muscles is made of **four strands**, - Since **its fibers** originate from **four different places**: 1. **First strand**: Originates from the **clavicle**, - Its fibers attach to the **corners of the mouth** and **pull the mouth downward**. 2. **Second strand**: Originates from both the **sternum** and **clavicle**, - Extends diagonally across the cheek, - The fibers from the right side cross to the **lower left lip corner**, - And those from the left side cross to the **lower right lip corner**. - When these fibers contract, they **tighten the mouth**, pushing it **forward**, like drawing a string across a pouch. 3. **Third strand**: Originates near the **shoulder joint (al-akharm)**, - Extends upward, - Joins the previous cheek muscles, - And pulls the lips **sideways** in a **symmetrical** fashion. 4. **Fourth strand**: Originates from the **cervical vertebrae**, - Passes near the **ears**, - Connects to parts of the **cheek**, causing it to **move visibly**, - The movement of the cheek is then followed by the movement of the lips. - In some people, this strand runs very close to the **base of the ear**, - And may connect to it, **causing the ear to move**.   **Chapter Seven:** ### **On the Muscles of the Lips** The **lip muscles** include both **shared** and **specific** components: - Some muscles are shared with the **cheek**, as mentioned above. - Some are **exclusive to the lips**. There are **four exclusive muscles**: - A **pair** coming from **above**, near the cheekbones, - And **two** from **below**. These **four are sufficient** for moving the lips **independently**, because: - Each one moves the lip **toward its respective side**. - When **two from opposite sides** move together, they **expand the lips outward**, - Enabling movement in all **four directions** — up, down, left, and right. These muscles, along with the ends of the shared cheek muscles, are **so deeply embedded** in the substance of the lips that: - **Tactile sensation** cannot distinguish them from the **natural tissue** of the lips. - The lips are **soft, fleshy organs** without any **bone** in them.   **Chapter Eight:** ### **On the Muscles of the Nostrils** The **tips of the nose (al-arnabah)** have **two small but strong muscles** attached to them. - They are **small**, so they don’t interfere with other facial muscles that are **used more often** — especially those of the **cheeks and lips**, which are **more numerous**, **more frequently used**, and **more essential**. - They are **strong** to compensate for the **absence of bone** at the nasal tip. - These muscles originate from the **cheek area**, - Initially mingling with the **fibers of the cheek**. - They arise from **both sides**, as movement of the nose tip is directed **toward them**.   **Chapter Nine:** ### **On the Muscles of the Lower Jaw** The **lower jaw (mandible)** was granted **exclusive movement** — unlike the upper jaw — for several reasons: 1. **Moving the lighter part is more efficient.** 2. The **upper jaw contains more delicate and vital organs**, so movement would disturb them. 3. If the **upper jaw** were easily movable, the **joint with the skull** would not be securely fixed. The movements of the lower jaw do not require more than **three actions**: - **Opening the mouth**, - **Closing it**, - **Chewing and grinding**. Each of these has its own muscles: - **Opening (al-faghār)** lowers the jaw. - **Closing (al-i****ṭ****bāq)** raises it. - **Chewing (al-sa****ḥ****q)** shifts it side to side. #### **Muscles for Closing the Jaw** - These include **two muscles**, known as the **temporal muscles (****ʿ****a****ḍ****latā al-ṣudgh)**, or the “twisters” (al-multafatayn). - They are relatively **small** in humans because: - The jaw is **light** in weight and structure. - Human chewing is **less forceful** compared to animals. In animals, the **lower jaw is heavier**, and the **chewing actions** such as biting and crushing are **stronger**. These muscles are **flexible** due to: - Their **proximity to the brain**, a very delicate organ. - Their **path avoids direct exposure** to the brain’s surface to prevent injury. Thus, the **Creator hid** these muscles near their origin in the **temporal bone (****ʿ****a****ẓ****m al-zawj)**, passing them through a canal formed from that bone’s crevices. - This gives the muscle **distance** to harden slightly and move away from the brain’s soft matter. Each of these two muscles forms a **large tendon** that covers the **edge of the lower jaw**. - When it **contracts**, it **raises** the jaw. #### **Supporting Muscles** Two **additional muscles** help from **inside the mouth**, - Running **downward** into the jaw from two **pockets (maqāzatayn)**. - Because **lifting heavy objects** requires **supporting force**, these two assist with upward movement. The tendon from these muscles arises from the **middle**, not the ends, for added **strength**. **Muscles for Opening the Jaw (Faghār)** - Their fibers originate from the **styloid processes** behind the ears. - They unite into **one muscle**, then form a **tendon** to enhance strength, then swell again into muscle, - And are known as the **"repeating muscle" (al-mukarrara)** to prevent excessive extension or injury. This muscle meets the **curve of the jaw near the chin**, - So when it contracts, it **pulls the jaw backward**, naturally causing **descent**. Because **gravity assists in lowering**, two muscles suffice without need for more. #### **Muscles for Chewing** There are **two triangular muscles**, one on each side: - Each has a **pointed angle** at the **cheekbone**. - One leg runs **down to the jaw**, the other **up to the temporal region**. - A **straight base** connects the two limbs. - Each corner attaches to what lies beneath it, - Giving the muscle the ability to **contract in various directions**, enabling **sideways motion** of the jaw.   **Chapter Ten:** #### **On the Muscles of the Head** The head possesses both: - **Exclusive movements**, and - **Shared movements** with the first five **vertebrae of the neck**, resulting in **combined motion** of both the head and neck. Each of these movements — whether exclusive or shared — may be: - **Forward bending (naks)**, - **Backward bending (inqilāb)**, - **Tilting right or left**, - Or a **rotational twisting (iltifāt)**, combining those motions. #### **Muscles That Flex the Head Alone (naks al-ra****ʾ****s)** There are **two muscles**, arising from **behind the ears**: - Their fibers attach both to the **back of the ear region (fawq)** and to the **bones of the nape (al-qas)** below. - They **ascend** in a connected path and are sometimes described as: - A **single muscle**, or - **Two muscles**, or - **Three**, because one of them splits at the top into **two heads**. If **one muscle contracts**, the head tilts **forward and toward that side**. If **both contract**, the head bends **straight forward**. **Muscles That Flex the Head and Neck Together** There is a **pair** of muscles beneath the **esophagus**, - Extending to the **first and second vertebrae**, and fusing with them. - If the part near the **esophagus** contracts, it bends the **head**. - If the fused part near the **vertebrae** contracts, it bends the **neck**. #### **Muscles That Extend the Head Backward** There are **four pairs** of muscles **tucked beneath** the ones just described. - Their **origins** are above the joint (fawq al-mafṣal). They include: - A pair from the **spinous process** of the **second vertebra** (centered), - A pair from the **wings of the first vertebra**, - A third that runs **diagonally** from the wing of the **first vertebra to the spine of the second**, - And a **fourth pair** that begins from **above**, passing **obliquely under the third**, toward the **side**, and then attaches to the **wing of the first vertebra**. - The **first two pairs** tilt the head **back** either directly or with slight lateral tilt. - The **third pair** balances sideways tilt. - The **fourth pair** tilts the head **backward** with **clear diagonal rotation**. - If the **third or fourth** acts **alone**, the head turns **toward its side**. - If they **contract together**, the head moves **straight backward**. #### **Muscles That Extend Both Head and Neck** There are **three pairs** of **deep muscles**, plus one **outer pair**: - The outer pair has **triangular portions**, with the base at the **occipital bone**, descending into the **neck**. The **three inner pairs**: - One runs along the **sides of the vertebrae**, - Another slants strongly **toward the wing-like processes**, - And the third lies **between** these two paths. #### **Muscles That Tilt the Head Sideways** There are **two pairs**: - The **first pair** is located **anteriorly**, connecting the **head** with the **second vertebra** (one to the right, one to the left). - The **second pair** is **posterior**, connecting the **first vertebra** to the **head**, again one on each side. - If any of these **four muscles** contracts, the head tilts **toward that side** with rotation. - If **two muscles** on the **same side** contract, the head tilts without rotation. - If the **anterior pair** contracts, they also assist in **forward bending**. - If the **posterior pair** contracts, they pull the head **back**. - If **all four** contract together, the head is held **upright and steady**. These four muscles are the **smallest** of the head muscles, - But they are **well-positioned**, protected beneath the larger muscles, - And **compensate for their size** with efficient placement. #### **Balancing Function: Strength & Flexibility** The **head joint** needed to fulfill **two contradictory roles**: 1. **Firm support** (al-wathāqa), which requires **joint stiffness**, 2. **Multiple movements**, which require **looseness and flexibility**. This was achieved by: - Allowing **some looseness in the joint**, while - Surrounding it with **numerous overlapping muscles**, securing and guiding movement. Thus, both **firmness** and **flexibility** were achieved — **Blessed is God, the best of creators, Lord of the Worlds.**   **Chapter Eleven:** ### **Anatomy of the Muscles of the Larynx** The **larynx (al-****ḥ****anjara)** is a **cartilaginous organ** created as an **instrument for sound production**. It consists of **three main cartilages**: 1. **Thyroid cartilage (al-ghu****ḍ****rūf al-daraqī)** – This is the **one that can be felt externally**, located at the **front of the throat, beneath the chin**. - It is called *"thyroid"* or *"shield-like"* because: - The **inner surface** is **concave**, - The **outer surface** is **convex**, - It resembles a **shield (dir****ʿ****)** or **part of a buckler (turs)**.   1. **Cricoid cartilage (al-ghu****ḍ****rūf al-halqī)** - This cartilage lies **beneath** the thyroid cartilage. - It is shaped **like a ring**, with a **narrow front** and a **wider back**, resembling a **signet ring** (*khatm*). - It serves as the **base** for the larynx and connects it to the **trachea (al-sha****ʿ****b al-haw****ā****ʾ****ī****yah)**. - It provides **support** and **stability** for the entire structure. 2. **Epiglottis (al-ghu****ḍ****rūf al-lisānī)** - This is a **leaf-shaped** cartilage located **behind the root of the tongue** and **above the larynx**. - It **bends downward** during swallowing to **cover the laryngeal opening**, thereby preventing food and drink from entering the **airway**. - Its function is **protective**, ensuring that the **path of respiration** remains **separate** from the **digestive tract**.   These three cartilages — **thyroid**, **cricoid**, and **epiglottis** — form the essential framework of the **larynx**, allowing for: - The **generation of sound** through vibration, - The **control of airflow**, - And the **protection of the respiratory passage** during swallowing. **Muscles Associated with the Larynx** The **larynx**, being a **delicate and critical organ**, is supported by a set of **precisely arranged muscles** that regulate: - The **tension** and **position** of its cartilages, - The **opening** and **closing** of the vocal cords, - And the **modulation of sound**. These muscles are categorized into two groups: 1. **Extrinsic Muscles** These muscles **connect the larynx** to surrounding structures, such as the **hyoid bone**, **sternum**, and **pharynx**. Their role is to: - **Raise or lower** the larynx during swallowing or speech, - **Stabilize** the laryngeal structure. Examples include: - **Sternothyroid muscle**, which pulls the larynx **downward**, - **Thyrohyoid muscle**, which **elevates** the larynx by drawing it toward the hyoid bone. 1. **Intrinsic Muscles** These muscles are located **within the larynx itself**, and they control the **movement of the vocal cords** and cartilages. They are responsible for: - **Opening** (abduction) and **closing** (adduction) of the **glottis**, - **Tension adjustment** for pitch modulation. Important examples include: - **Posterior cricoarytenoid muscles** – the **only muscles** that open the vocal cords, - **Lateral cricoarytenoid muscles** – **close** the vocal cords for sound production, - **Cricothyroid muscles** – **tighten** the vocal cords for **higher-pitched sounds**, - **Thyroarytenoid muscles** – **relax** the cords for **lower pitches**. These intrinsic muscles are controlled by **motor nerves**, primarily the **recurrent laryngeal nerve**, a branch of the **vagus nerve**, except the cricothyroid muscle, which is innervated by the **external branch of the superior laryngeal nerve**.   #### **Mechanism of Voice Production (Phonation)** The **larynx** is not only a passage for air but also an intricate **sound-producing apparatus**. Its ability to produce **voice** depends on the precise coordination of: - **Air pressure** from the lungs, - The **position and tension** of the **vocal cords** (located within the larynx), - And the **resonance** provided by the **pharynx**, **oral cavity**, and **nasal passages**. The **vocal cords** (also called vocal folds) are two bands of muscle tissue that: - **Open** during breathing to allow airflow, - **Close** when speaking or producing sound. When **air is exhaled** from the lungs, it **passes between the vocal cords**. If the cords are **brought close together** and placed under **proper tension**, they **vibrate**, producing sound. The **frequency** of these vibrations determines the **pitch**, and the **force** of air affects the **volume**. **Adjustments in pitch and tone** are made by: - **Tightening** the vocal cords via the **cricothyroid muscle**, leading to **higher pitch**, - **Relaxing** the cords via the **thyroarytenoid muscle**, resulting in **lower pitch**. The **articulation** of this sound into recognizable **speech** involves further coordination with the **tongue**, **lips**, **palate**, and **jaw**.   #### **Protective and Adaptive Functions of the Larynx** Beyond its role in **phonation**, the **larynx** plays a **vital protective role** in the human body: - During **swallowing**, the **epiglottis** folds down to **cover the glottis** (the opening between the vocal cords), preventing **food or liquid** from entering the **trachea** and instead directing it into the **esophagus**. - This **reflex action** is crucial in **preventing aspiration**, and is supported by the **timely coordination** of the **muscles of the pharynx**, **tongue**, and **larynx**. Moreover, the **cartilaginous structure** of the larynx — particularly the **cricoid** and **thyroid cartilages** — provides: - **Rigidity** to withstand the pressure of coughing, speech, and breathing, - **Flexibility** for precise **movement and modulation**, - **Resilience** against **external trauma** due to their shape and placement. **Summary of Divine Design** In this complex arrangement, the **Creator’s wisdom** is evident: - The **distribution of muscles**, **cartilages**, and **nerves** is precisely calibrated, - The **delicacy of vibration** is harmonized with the **strength needed** for protection and structural support, - The **dual function** of the larynx — as an **instrument of speech** and **a guardian of the airway** — reflects a purposeful and integrated design. Thus, the **larynx** stands as one of the finest examples of a **compound organ**, fulfilling multiple essential functions through a harmonious convergence of form, structure, and motion. --- **Chapter Twelve:** ### **Dissection of the Muscles of the Throat and Related Organs** The **throat**, being the passageway for **air** and **food**, is supported by a set of **specialized muscles** that facilitate **swallowing**, **speech**, and **respiration**. These muscles are carefully arranged around the **pharynx**, **larynx**, and **esophagus** to execute multiple coordinated actions. 1. #### **Muscles of the Pharynx** The **pharyngeal muscles** are organized in **circular** and **longitudinal** layers: - The **circular muscles** (the constrictors) function to **narrow** the pharyngeal space and **propel food downward** into the esophagus. - These are divided into **superior**, **middle**, and **inferior constrictor muscles**. - The **longitudinal muscles** act to **elevate** the pharynx and **widen** it during swallowing or speaking. - Chief among these are the **stylopharyngeus**, **palatopharyngeus**, and **salpingopharyngeus**. Together, these muscles coordinate to form a **peristaltic wave** during swallowing, ensuring food is safely directed into the esophagus while protecting the airway. 1. #### **Muscles of the Soft Palate** These muscles adjust the position of the **soft palate** to **seal off the nasal cavity** during swallowing and speech: - **Tensor veli palatini**: tenses the palate, - **Levator veli palatini**: elevates the palate, - **Palatoglossus** and **palatopharyngeus**: involved in closing the oropharyngeal isthmus. Their combined action prevents food from entering the **nasopharynx** during deglutition. 1. #### **Coordination and Control** The above muscles are governed by multiple **cranial nerves**: - The **vagus nerve (X)** innervates most pharyngeal and laryngeal muscles, - The **glossopharyngeal nerve (IX)** aids the stylopharyngeus, - The **trigeminal nerve (V)** and **facial nerve (VII)** contribute to certain muscles of the palate and mouth. The precise timing and strength of contraction in these muscles is essential for: - Safe swallowing, - Clear articulation in speech, - And preventing aspiration. --- **Chapter Thirteen:** ### **Dissection of the Muscles of the Tongue** The **tongue** is a unique organ composed almost entirely of **interwoven muscles**, allowing it extraordinary **mobility** and **dexterity**. These muscles are divided into two main groups: 1. #### **Intrinsic Muscles** These are located **entirely within the tongue**, and are responsible for **changing its shape**—such as lengthening, shortening, curling, or flattening. - They include **longitudinal**, **vertical**, and **transverse** muscle fibers. - They allow the tongue to adapt during **speech**, **chewing**, and **swallowing**, by modifying its **form**, not its position. 1. #### **Extrinsic Muscles** These muscles originate **outside** the tongue and insert into it, moving the tongue as a whole. - **Genioglossus**: protrudes and depresses the tongue, - **Hyoglossus**: depresses and retracts the tongue, - **Styloglossus**: elevates and retracts the tongue, - **Palatoglossus**: assists in raising the back of the tongue. Each of these muscles contributes to coordinated movements essential for **speech articulation**, **food manipulation**, and **swallowing**. **Innervation and Function** - The **hypoglossal nerve (XII)** controls all tongue muscles except the palatoglossus, - The **vagus nerve (X)** governs the palatoglossus. The tongue’s **flexibility and power** come from its being a **muscular hydrostat**—an organ that maintains its volume while changing shape. This makes it ideally suited for complex tasks in **language** and **nutrition**. ### ** Cartilages and Muscles of the Larynx** The **second cartilage** is situated below the neck, attached to it, and is known as the **one without a name**. The **third cartilage** is situated over the other two, connecting with the **nameless one**, and meeting the **thyroid cartilage** without directly joining it. Between it and the **nameless cartilage** is a **compound joint** with **two notches**, into which fit **two projections** from the **nameless cartilage**, attached via ligaments. This third cartilage is referred to by some as the **Meccan cartilage** (*al-Makkī*) or the **Tartajhārī**. When the **thyroid cartilage** approaches the **nameless one**, or recedes from it, the **larynx widens or narrows** accordingly. When the **Tartajhārī cartilage** folds onto the **thyroid** and adheres to it, or pulls away from it, the **laryngeal opening opens or closes**. In front of the larynx, there lies a **triangular bone** called the **hyoid bone (al-****ʿ****a****ẓ****m al-lāmī)**, named for its **resemblance to the Greek letter lambda (λ)** due to its shape. The **benefit** of this bone’s formation is that it serves as a **base and support** from which originate the **ligaments and muscles of the larynx**. #### **Muscular Mechanisms of the Larynx** The **larynx** requires a set of **specialized muscles**: 1. **Muscles that bring the thyroid cartilage closer to the nameless cartilage**, 2. **Muscles that draw the Tartajhārī (epiglottis or arytenoid) downward to close the larynx**, 3. **Muscles that pull the Tartajhārī away from the other two**, thereby **opening the larynx**. Among the **laryngeal-opening muscles**, there is: - A **pair** originating from the **hyoid bone**, which extends to the **front of the trachea**, spreading across it. - When these muscles **contract**, they **pull the Tartajhārī forward and upward**, thus **expanding the laryngeal space**. Another **pair**, commonly classified as **pharyngeal muscles** that also pull downward, may be counted among the **shared muscles** because: - They **originate from the inner thorax** and **insert into the thyroid cartilage**. In many animals, these muscles are accompanied by **another pair**, and even **two more pairs**: - One pair originates **behind the Tartajhārī**, attaches to it, and when contracted, **lifts it upward and pulls it backward**, separating it from the thyroid cartilage and **widening the laryngeal opening**. - Another pair attaches to the **sides of the Tartajhārī**; when they contract, they **pull it away from the thyroid cartilage and stretch it laterally**, contributing to the **expansion of the larynx**.   #### **Muscles That Constrict the Larynx** Among the muscles that **narrow** the laryngeal passage, there is: - A **pair** that originates from the **region of the hyoid bone**, attaches to the **thyroid cartilage**, then wraps around the **nameless cartilage** (likely the cricoid), with both ends meeting **behind it**. - When this pair **contracts**, it **tightens** the laryngeal opening. - There are also **four muscles** (often mistaken for a **doubled pair**) that connect the ends of the **thyroid** and the **nameless cartilage**. - When they **contract**, they **narrow the lower part** of the larynx. - Some believe that **one pair lies internally** and the other **externally**.   #### **Muscles That Close the Larynx** The most effective configuration for **closing the larynx** is to place the **muscles inside** the laryngeal cavity: - When they **contract**, they **pull the Tartajhārī downward** and **seal the larynx**. These consist of a **pair** that: - Originate from the **base of the thyroid cartilage**, - Ascend **internally**, attaching to the **edges of the Tartajhārī**. Another set arises from the **base of the nameless cartilage**, one from the **right side**, one from the **left**, and: - When these **contract**, they **tighten the joint** and bring about a **firm closure** of the larynx. These closing muscles are: - **Small** (to avoid crowding the internal space), - But **strong**, to compensate for their size by exerting enough **force to resist the pressure** of chest and diaphragm during breath-holding. Their path runs **nearly straight**, with only a **slight curve**, allowing them to link the **thyroid cartilage** with the **nameless one**. Sometimes, there are also **two additional muscles** located **beneath the Tartajhārī**, assisting the aforementioned pair. --- **Chapter Twelve:** ### **Dissection of the Muscles of the Throat (****الحلقوم****)** The **throat (****ḥ****ulqūm)** is moved by **two main muscle pairs** that pull it **downward**: 1. The **first pair** was previously mentioned in the chapter on the **larynx**, 2. The **second pair** originates from the **thorax** and ascends to attach to the **hyoid bone**, then to the **throat**, pulling it downward.   #### **Muscles of the Pharynx (****الحلق****)** The pharynx has two distinctive muscles known as the **naġnaġatān (****النغنغتان****)**: - These are **two muscles** located near the **throat**, - They play a **supportive role** in the act of **swallowing (****الإزدراد****)**. **Know this**, as it is of importance in understanding the mechanics of swallowing.   **Chapter Thirteen:** ### **Dissection of the Muscles of the Hyoid Bone (****تشريح عضل العظم اللامي****)** The **hyoid bone** has muscles that are: 1. **Exclusive to it**, and 2. **Shared with other organs**. 1. **Muscles Exclusive to the Hyoid Bone** These are **three pairs**: 1. **First Pair**: - Originates from the **sides of the lower jaw (****اللّحى****)**, - Attaches to the **straight line (****الخَط المُستقيم****)** on the hyoid bone, - Function: **Pulls the hyoid bone toward the jaw**. 2. **Second Pair**: - Begins **under the chin**, - Passes **beneath the tongue** to the **upper tip** of the hyoid, - Function: Also **draws the hyoid bone toward the jaw**. 3. **Third Pair**: - Originates from the **styloid processes (****الزّوائد السهمية****)** near the ears, - Attaches to the **lower tip** of the hyoid’s straight line. 1. **Muscles Shared with Other Organs** These were **mentioned before** and will be **discussed again** in their respective contexts.   **Chapter Fourteen:** ### **Dissection of the Tongue Muscles (****تشريح عضل اللسان****)** The muscles that **move the tongue** are **nine in total**: 1. **Two lateral muscles (****معرضتان****)**: - Originate from the **styloid processes (****الزوائد السهمية****)**, - Insert into the **sides of the tongue**, - Function: Move the tongue **side to side**. 2. **Two longitudinal muscles (****مطولتان****)**: - Originate from the **upper part of the hyoid bone**, - Insert at the **base of the tongue**, - Function: **Lengthen** the tongue. 3. **Two oblique (diagonal) muscles (****تحركان على الوراب****)**: - Originate from the **lower ridge of the hyoid bone**, - Pass between the **longitudinal and lateral muscles**, - Function: Move the tongue **diagonally**. 4. **Two depressor muscles (****باطحتان****)**: - Located **beneath** the previously mentioned muscles, - Spread their fibers **horizontally**, - Attach to the **entire lower jaw**, - Function: **Flatten and press** the tongue downward. 5. **One central unpaired muscle**: - Connects the **tongue** with the **hyoid bone**, - Function: **Draws one toward the other**. It is also plausible that: - The **longitudinal muscle** extending toward the **front of the tongue** also **protrudes** it, - Since it can both **extend** and **contract** within itself to perform this function.   **Chapter Fifteen:** ### **Dissection of the Neck Muscles (****تشريح عضل العنق والرقبة****)** The muscles that **move the neck** consist of **two main pairs**: 1. **A right-side pair**, 2. **A left-side pair**. - If **one side contracts alone**, the **neck bends toward that side** at an **angle**. - If **both muscles on one side contract together**, the neck **leans toward that side** **without angling**, maintaining a **straight posture**. - If **all four muscles contract at once**, the neck becomes **erect**, held upright with **no tilt** in any direction.   **Chapter Sixteen:** ### **Dissection of the Chest Muscles** The muscles that **move the chest** include: 1. **Muscles That Expand the Chest (****الباسطة****)** 1. **The diaphragm (****الحجاب الحاجز****)**: - Separates the **organs of respiration** from those of **digestion**. - Its action: **expands the chest**, but **does not compress it**. 2. **A paired muscle beneath the clavicle**: - Originates from a portion extending to the **head of the shoulder**, - Connects to the **first rib** on both the right and left sides. 3. **Another paired muscle, each with two parts**: - The **upper part** connects to the **neck** and moves it, - The **lower part** moves the **chest** and interacts with a third muscle connecting to the **fifth and sixth ribs**. 4. **A pair embedded in the concave area of the shoulder**: - Connects to another pair descending from the **vertebrae to the shoulder**, - These function together as **a single muscle** and attach to the **rear ribs**. 5. **A third pair**: - Originates from the **seventh cervical vertebra** and the **first two thoracic vertebrae**, - Inserts into the **sternal ribs**. These are the **main chest-expanding muscles**.   ### **Muscles That Constrict the Chest (****العضل القابضة للصدر****)** These muscles compress the chest in two main ways: 1. **Transverse compression**: - Performed by the **diaphragm** when it **relaxes**. 2. **Direct contraction**: - A **paired muscle** stretches beneath the **upper ribs**, functioning by **tightening and drawing together** the chest. - Another **pair** is located at the **ends of the ribs**, adhering to the **sternum**, between the **xiphoid process and the clavicle**, also connecting to the **rectus muscle** of the abdomen. - **Two additional pairs** assist in this compressive action.   ### **Muscles That Both Expand and Contract the Chest** These are the **intercostal muscles** (between the ribs). However, **careful examination** reveals: - That the **constricting** and **expanding** functions may be carried out by **separate muscle layers**, even though they appear as one. Between **every two ribs**, there are actually **four muscle layers**, though commonly mistaken for one. Their fibers are arranged as follows: - Some run **obliquely**, located **internally**, - Others are **external** and lie over different parts of the rib — - Either over the **cartilaginous end** (softer) or the **bony end** (stronger), - The arrangement of internal and external fibers **differs completely**. Thus: - If there are **four distinct fiber orientations**, then there must be **four distinct muscles**. So, generally: - The **upper-positioned muscles** act to **expand** the chest, - The **lower-positioned ones** act to **contract** it. The total number of chest muscles thus reaches **eighty-eight (88)**. Additionally: - Two more muscles arise from the **clavicle to the head of the shoulder**, - They attach to the **first rib**, - And help **raise it upward**, assisting in the **expansion of the chest**.   **Chapter Seventeen:** ### **Dissection of the Muscles That Move the Upper Arm** These are the muscles that act on the **shoulder joint** to move the **upper arm (****العضد****)**. #### **Muscles Originating from the Chest (****ثلاث عضلات****)** These three muscles **pull the arm downward**: 1. **Muscle 1**: - Originates from **beneath the breast**, - Inserts at the **front of the humerus**, near the **clavicle**, - Function: **Draws the arm toward the chest**, causing the **shoulder to drop**. 2. **Muscle 2**: - Originates from the **top of the sternum**, - Wraps around the **inner head of the humerus**, - Function: **Draws the arm toward the chest** with a **slight upward lift**. 3. **Muscle 3 (large, double)**: - Originates from the **entire sternum**, - Inserts into the **lower front of the humerus**, - Its action varies: - **Upper fibers** raise the arm toward the chest, - **Lower fibers** lower it, - Or both together pull it **straight inward**. #### **Muscles from the Flank Area (****عضلتان من ناحية الخاصرة****)** 1. **Large muscle**: - Originates from the **flank and rear ribs**, - Draws the arm **straight back** toward the ribs. 2. **Smaller muscle**: - Arises from the **skin over the flank**, not from the bone, - Slightly **more medial** than the larger one, - Inserts into the **tendon** of the large chest muscle, - Assists in the same action but **with a slight backward pull**. #### **Muscles Originating from the Shoulder Blade (****خمسة عضلات من عظم الكتف****)** 1. **Muscle 1**: - Fills the space between the **ridge and upper border** of the scapula, - Inserts into the **upper outer head of the humerus**, - Function: **Abducts the arm**, with slight inward angling. 2. **Muscles 2 & 3**: - Both arise from the **upper ridge of the scapula**: - **Muscle 2 (large)**: - Spreads across the **lower ridge**, - Inserts into the **outer head of the humerus**, - Function: **Abducts and rotates outward**. - **Muscle 3 (adjacent to 2)**: - Appears as a **continuation**, - Inserts nearby, with a **similar function**, - But more superficial and angled **across the deltoid**. 3. **Muscle 4**: - Fills the **concave inner surface** of the scapula, - Inserts into the **inner head of the humerus**, - Function: **Rotates the arm backward**. 4. **Muscle 5**: - Originates from the **lower part** of the scapula, - Inserts **above the insertion** of the large flank muscle, - Function: **Lifts the upper arm upward**. 1. **A Biceps-like Muscle (****عضلة ذات رأسين****)** - This muscle has **two heads** and performs **three actions**: 1. **Originates from below the clavicle and the neck**, 2. Inserts into the **head of the humerus**, 3. Lies near the **insertion of the large chest muscle**. - One head is **deep and angled inward**, - The other is **superficial and angled outward**, - When both act together, they **lift the arm straight up**. 1. **Additional Muscles (****عضلتان إضافيتان عند بعض الناس****)** - **One small muscle from the chest**, - **One additional muscle** (possibly not named), mentioned as sometimes present. --- **Chapter Eighteen:** ### **Dissection of the Muscles That Move the Forearm** These muscles perform **three primary actions**: - **Flexion (****قبض****)** - **Extension (****بسط****)** - **Rotation**: Pronation (كبّ) and Supination (بَطح) 1. **Extensor Muscles (****العضل الباسطة****)** These are **a pair**, with distinct orientations: 1. **First muscle**: - Originates from **below the front of the upper arm** (العضد), - Also from the **lower rib** and **shoulder**, - Inserts at the **inner part of the elbow**, - Function: **Extends the forearm**, with a **slight inward angle**. 2. **Second muscle**: - Originates from the **shaft of the humerus (****فقار العضد****)**, - Inserts at the **outer elbow**, - Function: **Extends the forearm**, with a **slight outward angle**. → Together, they **extend the forearm in a straight line**. #### **Flexor Muscles (****العضل القابضة****)** These are also a **pair**: 1. **First muscle (larger)**: - Originates from the **lower ulna (****الزند الأسفل****)** and **coracoid process (****المنقار****)**, - Passes **inward** along the arm, - Inserts at the **upper part of the ulna**, - Function: **Flexes inward**. 2. **Second muscle**: - Originates from the **outer rear side** of the humerus, - Has **two fleshy heads**, - One behind the humerus, - The other in front, - Passes deeply and inserts at the **front of the lower ulna**, - Function: **Flexes outward**. → These two work together to **flex the forearm directly**, with **greater control** due to opposing angles. #### **Underlying Muscle (****عضلة مستبطنة****)** - A muscle beneath the extensors, - Wraps around the **humerus**, - Possibly part of the **second flexor**. 1. **Supinator Muscles (****العضل الباطحة****)** These **flatten or rotate the forearm outward**: 1. **First**: - External, between the two ulnae, - Meets the **upper ulna** without a tendon. 2. **Second**: - Thin, long, originates from the **upper outer humerus**, - Runs through the forearm to near the **wrist joint**, - Inserts at the **inner tip of the upper ulna** via a **membranous tendon**. #### **Pronator Muscles (****العضل المكبة****)** These **rotate the forearm inward**: 1. **First**: - External, from the **upper inner humerus**, - Inserts at the **upper ulna**, before the wrist. 2. **Second**: - Shorter, more **fibrous**, - Originates from the **lower ulna**, - Inserts at the **upper ulna** near the **wrist joint**.   **Chapter Nineteen:** ### **Dissection of the Muscles That Move the Wrist Joint** The muscles that move the **wrist joint (****مفصل الرسغ****)** fall into **four categories**: 1. **Flexors (****قابضة****)** – bend the wrist inward 2. **Extensors (****باسطة****)** – straighten or lift the wrist 3. **Pronators (****مكبة****)** – rotate the wrist **inward** (palm-down) 4. **Supinators (****باطحة على القفا****)** – rotate the wrist **outward** (palm-up, toward the back)   #### **Muscles of the Wrist** Among the **extensor muscles** is one that is **connected to another**, such that they appear as **a single muscle**, although: - The **first originates** from the **middle of the lower ulna** and its **tendon inserts** into the **thumb**, helping it **move away from the index finger**. - The **second originates** from the **upper ulna** and its **tendon connects** to the **first wrist bone**, aligned with the thumb. - When both move together, they **extend the wrist** with **slight pronation**. - When the **second alone** acts, it **supinates** the wrist. - When the **first alone** acts, it **separates the thumb from the index finger**. Another muscle: - Lays across the **outer upper ulna**, - Originates from the **lower end of the humerus**, - Sends a **bifurcated tendon** to the **middle metacarpal**, between the **middle and index fingers**, - With the tendon leaning on the **upper ulna** near the wrist, - It **extends the wrist** with some **pronation**. As for the **flexor muscles**, they consist of a **pair** on the **outer side of the forearm**: - The **lower of the two** originates from the **inner head of the humerus** and ends at the **metacarpal of the pinky**. - The **upper** originates slightly higher and ends in the same area. There is a **third muscle**, located between the two: - It originates from the **lower parts of the humerus**, - Crosses diagonally with **two fascicles**, - Inserts into the **area between the index and middle fingers**. - When both act, they cause **contraction**. Thus, these flexors and extensors also cause **pronation and supination**: - If opposing muscles move **diagonally**, - For instance, the **muscle connected to the pinky** when acting alone, **turns the palm over**, - If **assisted by the thumb muscle**, which will be discussed shortly, the hand is fully **supinated**. The **muscle connected to the front of the wrist**, in line with the **thumb**, when acting alone **pronates it slightly**, and with the **pinky-side muscle**, it **fully pronates** it. **Know this well.** --- **Chapter Twenty:** ### **Dissection of the Muscles That Move the Fingers** The muscles that move the fingers are of **two types**: 1. Those located **in the palm** (في الكفّ), and 2. Those located **in the forearm** (في الساعد). If all these muscles were concentrated in the palm, the **weight of the flesh** would make the hand too heavy. Moreover, since the **wrist muscles** are far from the fingers, their **tendons had to be made long**, which is why: - These tendons are **reinforced with sheaths** from all sides, - And created **round and strong**, - Only flattening out when reaching the finger bones to provide **secure attachment** to the moving digits.   #### **Extensor Muscles for the Fingers** - All **extensor muscles** lie in the **forearm**, - As do those that move the fingers **downward**. **The Main Extensor:** - A single muscle, located at the **center of the forearm’s dorsal side**, - Originates from the **lower projecting part of the humerus**, - Sends **four tendons** to the **four fingers**, extending them.   #### **Downward-Acting Muscles (Flexor-Side of Movement)** There are **three muscles**: 1. The **first**, connected partly to the others, - Arises from the **middle part** between the two projections of the **outer humerus**, - Sends **two tendons** to the **ring and little fingers**. 2. The **second**, part of a **doubled muscle pair**, - Originates from the **lower inner projection of the humerus**, - And from the **edge of the lower ulna**, - Sends **two tendons** to the **middle and index fingers**. 3. The **third** arises from the **upper part of the upper ulna**, - Sends a **tendon to the thumb**. - Near it is another muscle (previously discussed in wrist motion), - Originates from the **middle of the lower ulna**, - Its **tendon pulls the thumb away from the index**.   #### **Flexor Muscles of the Fingers** Some are located in the **forearm**, others in the **palm**. ##### **Forearm Flexors (Three Muscles):** - **Stacked one over the other**, in the middle of the forearm. 1. The **deepest and most noble**, - Hidden beneath others, - Originates from the **middle of the inner humeral head**, - Attaches to the **lower ulna**, - Sends **five tendons**, each entering a finger. - The **four outer tendons** flex the **first and third joints** of each finger: - The **first joint** is encircled with ligaments, - The **third joint** is reached by the tendon head. - The **thumb tendon** flexes its **second and third joints**. 2. The **second muscle**, smaller than the first: - Originates from the **inner head of the humerus**, - Slightly attaches to the **lower ulna**, - Travels along the **shared ridge** between outer and inner sides, - When it reaches the thumb area, it **bends inward**, - Sends **tendons to the middle joints** of the four fingers. - Sends a **branch to the thumb**, but **not directly** from its main tendon—rather from **another origin**. The **origin** of the first muscle is from the **lower and upper heads of the ulna**, While the **second originates** only from the **lower ulna**. - The **thumb** is assigned **one flexor**, - While the **four fingers** use **two**. - Because: - The **primary function** of the four fingers is **gripping**, - The **thumb’s function** is **spreading and extending**, especially separating from the index finger.   #### **Muscles in the Palm Itself** There are **eighteen muscles** in the palm, arranged in **two layers**: - A **lower (deep) row** closer to the inner hand (داخل), and - An **upper (superficial) row** closer to the skin (خارج). **Lower Layer (7 Muscles):** - **Five** of them **elevate** the fingers upward. - The **thumb muscle** arises from the **first wrist bone**. - The **sixth** is **short and broad**, with **oblique fibers**, - Its upper end connects to the **middle metacarpal**, - The tendon attaches to the **thumb**, pulling it **downward**. - The **seventh**, located at the **little finger**, - Originates from the metacarpal beneath it, - Pulls the pinky **downward**. None of these seven muscles serve for **gripping**: - **Five** are for **elevation (raising)** - **Two** for **lowering** (downward movement). **Upper Layer (11 Muscles):** - Located **beneath** the **flat muscle that spreads over the palm**, - This layer was identified **only by Galen (****جالينوس****)**. It includes: - **8 muscles** (in 4 pairs): - Each **pair** acts on the **first joint** of the **four fingers** (excluding thumb and pinky). - One muscle lies **above**, the other **below**. - The **lower muscle** flexes with **depression and lowering**, - The **upper** flexes with **slight elevation**, - Together, they allow for **balanced gripping**. - **3 muscles specific to the thumb**: - **One** flexes its **first joint**, - **Two** flex the **second joint**, as previously explained. In summary: - Each of the **four fingers** (excluding thumb and pinky) has **one stabilizing muscle**. - The **thumb and pinky** each have **two**. - Each finger has **four flexor muscles**. - Each has **one elevator muscle**. **Mark this well.** --- **Chapter Twenty-One:** ### **Muscles of the Spine (****الصلب****)** Spinal muscles fall into two categories: 1. Those that **extend the spine backward**, 2. Those that **bend it forward**. All other spinal movements branch from these two. 1. **Extensors of the Spine** - These are specifically called **“spinal muscles” (****عضل الصلب****)**. - They are **two main muscles**, each composed of **23 smaller muscles**. - Each arises from **every vertebra**, except the **first**. Each vertebra sends a **diagonal fiber**, forming a unified muscle. When extended **moderately**, the spine is **upright**. When overextended, it bends **backward**. If one side only contracts, the spine **bends toward that side**.   #### **Flexor Muscles of the Spine** There are **two pairs** of spinal flexors: 1. **Upper Pair** - Located **above** the diaphragm, - Among the muscles that **move the head and neck**, - They **pass alongside the esophagus**, - Their **lower ends** connect to the **top five thoracic vertebrae** (in some people), or **four** (in most). - Their **upper ends** extend into the **head and neck**. 1. **Lower Pair – Called "al-mutanayn" (****المتنين****)** - Located **below** the first pair, - Originate from the **10th and 11th thoracic vertebrae**, - Extend **downward**, - Bend the spine in a **downward curve**. These muscles suffice for **basic spinal movements**, Since the spine **follows the limbs** in bending, curving, and twisting.   **Chapter Twenty-Two:** ### **Muscles of the Abdomen** The **abdominal wall** consists of **eight muscles**, serving **shared functions**, such as: 1. **Assisting in expelling**: feces, urine, and even fetuses from the womb. 2. **Supporting the diaphragm**, especially during forceful **exhalation** or pressure buildup. 3. **Warming the stomach and intestines** through **internal heat generation**. **These Eight Muscles Include:** 1. **One vertical pair (****زوج مستقيم****)**: - Descends straight from the **thyroid cartilage** to the **pubis**, - Fibers run **vertically** and **expand** near the lower attachment. - Entirely **fleshy in texture**. 2. **Two transverse muscles**, crossing the vertical ones **horizontally**, - Located **above the abdominal membrane**, - Beneath the vertical pair. - Their fibers cross those of the vertical muscles at **right angles**. 3. **Two oblique (angled) pairs**: - One on each side (right and left). - Each pair includes **two intersecting muscles**, - Running from the **sternum to the pubis**, - And from the **flank to the throat**. - The **fibers of both sides** meet: - One set at the **pubis**, - The other at the **sternum**. - These pairs remain **fleshy** until they meet the **vertical muscles**, - Then transition to **broad tendon-like sheaths**, resembling **membranes**. These oblique muscles lie **above the vertical pair**, While the transverse muscles lie **beneath them**.   **Chapter Twenty-Three:** ### **Dissection of the Muscles of the Genitals** **For Men:** - The **testicles** are supported by **four muscles**. - These are designed to: - **Hold the testicles up**, - **Lift them**, - And **prevent them from sagging**. - Each testicle is controlled by its **own pair of muscles** (i.e., two muscles per testicle). **For Women:** - A **single pair** of muscles is sufficient—**one for each ovary**. - This is because: - Women’s ovaries are **not suspended externally** like the testicles in men, - Hence, **less muscular support** is needed.   **Chapter Twenty-Four:** ### **Dissection of the Muscles of the Bladder** Know that at the **opening (mouth) of the bladder**, there is a **single muscle** that: - **Encircles** the opening, - Is composed of **circular (transverse) fibers**. **Its Function:** - **Retains urine** until **voluntary release** is intended. - When urination is desired: - This muscle **relaxes**, - The abdominal muscles then **compress the bladder**, enabling expulsion of urine.   **Chapter Twenty-Five:** ### **Dissection of the Muscles of the Penis** The muscles that move the penis consist of **two pairs**: 1. **The First Pair:** - Each muscle **runs along one side** of the penis. - When these muscles **contract and extend**, they: - **Widen the urethral passage**, - **Straighten** the organ, - Allow **semen to pass easily** through the channel. 1. **The Second Pair:** - Originate from the **pubic bone**, - Attach to the **base of the penis** in a **diagonal orientation**. - When they **contract moderately**, the penis becomes **erect and straight**. - If they **contract forcefully**, they **pull the penis backward**. - If only **one side contracts**, the penis **tilts in that direction**.   **Chapter Twenty-Six:** ### **Dissection of the Muscles of the Anus** There are **four muscles** associated with the anus: 1. **The First Muscle:** - Closely surrounds the **anal opening**, - Intertwines deeply with the **flesh of the anal region**, - Similar to how **lip muscles** blend with the tissue of the lips. - Functions: - **Contracts** the anus, - **Closes** the opening, - **Expels residual waste** through **compression**. 1. **The Second Muscle:** - Located **deeper and higher** than the first (closer to the head in position), - Believed to have **two ends**, - Its ends connect to the **base of the penis**, quite literally. **3–4. The Remaining Two (a Pair):** - **Obliquely placed above all the others**, - Their function is to **elevate the anal region upward**. - The **protrusion of the anus** (prolapse) occurs **when these muscles relax** and fail to lift.   **Chapter Twenty-Seven:** ### **Dissection of the Muscles That Move the Thigh** The **largest thigh muscles** are: 1. Those that **extend** the thigh (باسطة), followed by 2. Those that **flex** it (قابضة), 3. Then those that **abduct** it (تبعده), 4. Then **adductors** (تقربه), 5. And finally those that **rotate** it (مديرة). Among these, **extension and flexion** are the **most noble** of functions, With **extension** being more important than **flexion**, Because **standing upright** is only possible through extension.   #### **Extensors of the Thigh Joint** 1. ##### **The Greatest Muscle in the Body** - **Covers the pubic bone** and the **hip**, - **Wraps around** the entire thigh from the **inside and back**, - Ends at the **knee**. - Its **fibers have varied origins**, leading to **diverse actions**: - Some fibers originate from the **lower part of the pubis**, and extend **inward**, - Others arise slightly **higher**, extending **upward only**, - Still others begin much **higher**, and wrap the thigh **inward and upward**, - Still others arise from the **hip bone**, and **extend the thigh** **directly and efficiently**. 1. ##### **Another Muscle:** - **Encircles** the entire **hip joint** from the **back**, - Has **three heads** and **two tendons**. - Its **heads** originate from: - The **flank**, - The **hip**, - The **coccyx**. - Two of these heads are **fleshy**, one is **tendinous**. - Its **two tendons** attach to the **posterior part of the femoral head**. - If **one tendon** contracts, it **extends** with a **tilt toward that side**. - If **both contract**, it **extends the thigh directly**. 1. ##### **Another Muscle:** - Arises from the **entire outer surface** of the **hip bone**, - Connects to the **greater trochanter** (trochanter major), - Extends **slightly forward**, and **extends** the thigh **with a medial tilt**. 1. ##### **A Similar Muscle:** - Connects first to the **lower part of the lesser trochanter**, - Then descends, producing a similar extension, though **milder**. It may be that this is a **compound muscle**, Originating from the **lower outer hip bone**. 1. ##### **Another Muscle:** - Originates from the **lower hip bone**, - Tilts **backward**, - Extends with a **slight backward tilt** and a **strong medial (inward) rotation**.   #### **Flexor Muscles of the Thigh Joint** 1. **A Muscle That Flexes With Slight Inward Tilt** - A **straight muscle**, - Descends from **two origins**: - One from the **lower back (metn)**, - The other from the **hip bone**. - It connects to the **lesser inner trochanter** (الزائدة الصغرى الإنسية), - And flexes the thigh with a **slight inward angle**. 1. **Another Muscle:** - Originates from the **pubic bone**, - Connects to the **lower part of the lesser trochanter**, - It also contributes to **thigh flexion**.   #### **Muscles of Thigh Movement (continued)** - A muscle runs **alongside** the major muscle on the **outer rear side**, almost appearing as part of the **gluteus maximus**. - A **fourth** arises from the **upright projection** of the **hip bone**, which also **pulls the leg** along with **thigh flexion**. **Adductor Muscles:** - Some of them were discussed under **flexion and extension**. - One adductor originates from the **pubic bone** and runs downward toward the **knee**. **Abductor Muscles:** - There are two muscles responsible for **abducting** the thigh outward: - One arises from the **broad pelvic bone**. **Rotator Muscles:** - Two muscles rotate the thigh: - One originates from the **outer side of the pubis**, - The other from the **inner side**. - They **merge** and attach at the **deep hollow** near the **posterior greater trochanter**. - When either contracts alone, it **rotates the thigh toward its side** with a slight extension.   **Chapter Twenty-Eight:** ### **Muscles Moving the Leg and Knee** #### **Extensors of the Knee:** - Three large muscles are located **at the front of the thigh**, the largest in the entire thigh. - Their action is to **extend** the leg. - One of them is **double-headed**: - One head from the **greater trochanter**, the other from the **front of the thigh**. - It has two ends: - A **fleshy end** connecting to the **kneecap (patella)**, - A **membranous end** connecting to the **medial femoral condyle**. - The other two: - One arises from the **hip partition**, already discussed in thigh flexors, - The other from the **lateral trochanter**. - They unite and form a **broad tendon** that wraps around and firmly binds the **kneecap**, - Then connects to the **upper tibia**, **extending the knee** and **leg**. - A fourth muscle, mentioned in some anatomical texts: - Originates from the **hip bone**, - Runs **obliquely on the outer side** to the **grooved area of the leg**, - Strongest in obliquity, extending the leg **laterally**. #### **Flexors of the Knee:** - One **long narrow muscle** originates from the **hip and pubic bones**, - Runs obliquely to the **inner side of the knee**, - Attaches to the **grooved area** there, drawing the leg **upward and inward** toward the **groin**. - Three other muscles: - **Lateral, medial, and central**, - The **lateral** and **central** flex with **outer tilt**, - The **medial** flexes with **inner tilt**, - All originate from the **base of the hip bone** and connect to the **grooved areas** of the tibia. - One muscle appears **buried in the knee fold**, acting like the central flexor. - Some believe a branch from the **double extensor muscle** may flex the knee **laterally**, - With a **tendon** that stabilizes the **hip socket**.   **Chapter Twenty-Nine:** ### **Muscles of the Ankle Joint** #### **Muscles That Raise the Foot:** - One **large muscle** in front of the **inner tibia**, - Originates from the **outer side of the tibial head**, - Passes toward the **big toe**, lifting the foot. - Another from the **outer head**, - Sends a tendon to the **base of the pinky**, helping lift the foot, especially when working with the first. #### **Muscles That Lower the Foot:** - A **pair of muscles** originates from the **femoral head**, - Fills the **posterior leg**, - Forms the **Achilles tendon**, pulling the **heel bone** backward and laterally, stabilizing the foot. - Another muscle from the **outer head**, **purple in color**, - Runs without forming a tendon, remaining **fleshy**, - Attaches above the heel. - A **bifurcated muscle**: - One branch flexes the **foot**, the other **extends the big toe**, - Originates from the **inner tibial head**, - Splits: one tendon reaches the **instep** to **lower the foot**, - The other passes to the **first toe joint**, extending it **inward**. - A muscle from the **outer femoral head** connects to one **Achilles muscle**, - Then diverges under the sole, - Spreads like the **palmar aponeurosis**, aiding in similar function.   **Chapter Thirty:** ### **Muscles of the Toes** ##### **Toe Flexors:** - One originates from the **outer tibial head**, - Sends a tendon that splits to flex the **middle and ring toes**. - A **smaller one**, from the **back of the leg**, - Its tendon splits to flex the **pinkie and index fingers**, - Tendons merge and reach the **big toe**. - A third muscle, previously mentioned, - Originates from the **outer inner tibial edge**, - Sends branches to **flex the foot** and **big toe**. ##### **Intrinsic Muscles of the Foot:** - Ten muscles **within the sole**: - Each toe has **two muscles**, one on each side, - They flex together for **straight grip**, or one side for **angled grip**. - Four muscles are at the **instep**, one for each toe. - Two special muscles for the **big toe** and **pinkie**. These muscles are **so interwoven** that: - Damage to one affects the **function of the rest**, - Which explains why **some toes are hard to flex individually**. #### **Toe Adductors/Abductors:** - **Five muscles** on the **top of the foot** tilt the toes **laterally**, - **Five below** connect each toe to its **medial neighbor**, pulling it **inward**. - Together with two more (for big toe and pinky), these form a group of **seven**, corresponding to the **third class** of foot muscles.   **Chapter Thirty-One:** ### **On the Nerves — Their Functions and General Origin** Nerves have two kinds of **functions**: 1. **Essential functions**, and 2. **Incidental (secondary) functions**. **Essential Function:** - The nerve's essential role is to **transmit the influence of the brain** to the other organs, whether for **movement or sensation**. #### **Incidental Functions:** - These include: - **Firming the flesh**, - **Strengthening the body**, - **Conveying sensations** from organs that normally **lack direct sensitivity**, such as the **liver, spleen, and lungs**. Even though these organs **lack sensory perception**, they are: - **Wrapped in nerve sheaths** and **covered by a nervous membrane**. So, when these organs become **inflamed**, or **distended with gas**, - Their sheaths sense the **pressure or expansion**, - Producing a **sensation** indirectly through **traction or inflation**. #### **Origin of the Nerves:** - The **true source** of nerves is the **brain**. - The **final distribution** of the nerves reaches the **skin**, which is filled with fine fibers and nerves from nearby organs. The brain is the origin of nerves in **two ways**: 1. For some, it is the **direct origin**, 2. For others, it is the **origin via the spinal cord**. #### **Distribution of Nerve Functions:** - Nerves **emerging directly from the brain** serve primarily: - The **head**, - The **face**, - And some **internal organs**. - All other body parts derive their nerve supply **indirectly** via the **spinal cord**. Galen observed that **special care** was taken in how the **nerves traveling from the brain to the internal organs** were constructed. Because of their **distance from the source**, God the Creator: - Fortified them with **additional layers**, - Surrounding them with a **substance intermediate** in texture between **nerve and cartilage**. This was necessary to **withstand twisting** and maintain **function**, - Especially in **three regions**: 1. At the **larynx**, 2. At the **roots of the ribs**, 3. Below the **thoracic cavity**. Other cranial nerves follow a different logic: - Those providing **sensation** travel in the **most direct path** to their destination, - Because **directness** allows for **stronger transmission** from the source. Sensory nerves require **softness** to conduct sensation well, Unlike motor nerves, which must be **more solid**. Motor nerves are routed through **twists and bends** to: - **Distance them** from the **brain's essence**, - And **gradually increase** in firmness. The **origin substance** of these nerves supports their functions: - Most **sensory nerves** originate from the **anterior brain**, which is **softer**, - Most **motor nerves** originate from the **posterior brain**, which is **thicker and firmer**.   **Chapter Thirty-Two:** ### **Dissection of the Cranial Nerves and Their Pathways** From the brain emerge **seven pairs of cranial nerves**. **The First Pair:** - Originates from the **anterior ventricles** of the brain, - Specifically from the **depths between the two frontal lobes**, - Near the **two protrusions** resembling **nipple-like structures**, which are associated with the sense of **smell**. - These nerves are **large and hollow**, - The right nerve extends to the **left**, - The left nerve extends to the **right**. - They **intersect at the optic chiasm**. - From there: - The **right nerve continues to the right eye**, - The **left nerve to the left eye**. - Their ends expand to **encapsulate the vitreous humor** of the eyes. Galen and others mentioned that **at the optic chiasm**, the nerves **do not simply cross** but rather **intertwine** — a structure that has **three benefits**: **First:** - It allows **fluid from one eye** to flow to the **other** if one is afflicted. - This helps each eye become **sharper** when the other is closed, - And **clearer** if only one is focusing. **Second:** - It ensures the two eyes **transmit a single unified image** to the brain. - The visual form is thus **merged** in a **shared visual field**. - When this unity is disturbed (such as in strabismus), the **same object appears as two**. **Third:** - The crossing allows the nerves to **support one another**, - Appearing as though **they originate near the eye** itself.   **The Second Pair:** - Arises **behind the origin** of the first pair, and slightly **laterally** from it. - It exits through the **foramen** located in the **depression** that **encloses the eyeball**. - It then **branches into the muscles of the eye**.   ### **Cranial Nerves and Their Pathways** **The Third Pair:** - Emerges near the **origin of the second pair**, - But descends **more deeply** and exits through another **skull opening**. - This nerve **branches into several parts**, - Some going to the **muscles that move the eyeball**, - Others extending to the **eyelids**. **The Fourth Pair:** - A **fine and delicate nerve**, - Arises **close to the root** of the **cerebellum**, - Travels obliquely and enters the **eye socket** to supply one of the **oblique eye muscles**. **The Fifth Pair:** - A **large and prominent nerve**, - Exits through the **temporal bone**. - This nerve **divides into three major branches**: 1. The first goes to the **forehead and upper eyelid**. 2. The second to the **upper jaw**, **teeth**, and **upper lip**. 3. The third to the **lower jaw**, **teeth**, **lower lip**, and also sends a branch to the **tongue** for **general sensation**. This is the nerve responsible for **facial sensitivity**, especially pain in **dental and facial areas**. **The Sixth Pair:** - Emerges from a point **deeper and more posterior** than the fifth, - Travels to the **eye socket**, - Supplies the **lateral rectus muscle** of the eye, responsible for **abducting** the eyeball. **The Seventh Pair:** - A **dual-function nerve**, composed of: - A **motor part**: supplying the **facial expression muscles**, - A **sensory part** (sometimes called the **intermediate nerve**): responsible for **taste in the anterior two-thirds of the tongue**. - This pair exits through the **stylomastoid foramen** behind the ear. - It is this nerve that becomes affected in **facial paralysis** (Bell’s palsy), when damaged or inflamed.   #### **Spinal Cord Nerves and Their Distribution** After the cranial nerves, the **remaining nerves** emerge from the **spinal cord**, which itself is an **extension of the brain**. These spinal nerves: - Exit in **pairs** from the **spaces between the vertebrae**. - Each nerve is composed of: - A **motor root** that arises from the **anterior part** of the spinal cord, - A **sensory root** that arises from the **posterior part**. These two roots **join together** after exiting the vertebral column and continue as a **single mixed nerve**. Spinal nerves are distributed to: 1. **The trunk**, including the chest and abdomen, 2. **The upper and lower limbs**, 3. **Internal organs**, through **plexuses** (nerve networks). **Plexuses:** There are several **major nerve plexuses**, where nerves intertwine and redistribute: - **Cervical plexus**: serves the **neck and diaphragm**. - **Brachial plexus**: serves the **shoulder and upper limbs**. - **Lumbar and sacral plexuses**: serve the **lower abdomen, pelvis, and lower limbs**. The nerves from the spinal cord **coordinate movement and sensation** in nearly all parts of the body outside the head. While cranial nerves primarily serve the **head and face**, spinal nerves take over the rest, making them critical for **voluntary movement**, **pain perception**, and **autonomic regulation** (like heart rate, digestion, etc.).   #### **Completion of the Cranial Nerves** **Third Pair (Expanded Description):** This pair is **very thick**, due to its **need for resilience and movement power**, especially since it is **near the origin (brain)**. It requires such strength because: - The **third pair** is dedicated entirely to the movement of a large structure—the **lower jaw**—and therefore cannot share its power. - It **needs an external helper**, as will be explained. **Fourth Pair:** - Originates from the **shared border** between the **forebrain and hindbrain**, at the **base of the brain**. - Initially, it **mingles with the third pair** slightly, then separates. - It **branches into four parts**: **First Branch:** - Exits from the **entry of the carotid artery**, - Descends through the **neck**, passes the **diaphragm**, and - Distributes into the **organs below the diaphragm**. **Second Branch:** - Exits through an opening in the **temporal bone**, - Joins with a nerve from the **fifth pair**, which will be detailed later. **Third Branch:** - Exits through the **same foramen** as the **second pair**. - Its destination is the **anterior facial organs**, and it avoids entering the foramen of the **first pair** so as not to disturb the more noble optic nerve. This branch **splits into three parts**: 1. One extends to the **temples, chewing muscles, eyebrows, forehead, and eyelids**. 2. Another goes through the **foramen near the inner canthus** to the **nasal cavity**, branching throughout its lining. 3. The third, larger part travels through the **zygomatic bone**, dividing into: - A branch that enters the **oral cavity** and supplies the **upper teeth** and **gums**. - Another that spreads to the **skin of the cheek**, **tip of the nose**, and **upper lip**. These are the divisions of the **third branch** of the **third pair**. **Fourth Branch of the Third Pair:** - Penetrates a foramen in the **upper jaw** toward the **tongue**, - Branches throughout its **outer surface**, providing the **sense of taste**, - Excess fibers branch into the **lower teeth**, **gums**, and **lower lip**. The part that reaches the tongue is **finer** than the optic nerve. **Fifth Pair:** - Originates from the **posterior region of the brain**, - Each branch **divides into two**, appearing almost as **two nerves per side**. **First Division:** - Extends to the **membrane lining the ear canal**, spreading throughout it, - Is responsible for **hearing**, - Originates from the **posterior part of the brain**. **Second Division (Smaller):** - Emerges from the **petrous portion** of the temporal bone, - Nicknamed the **twisted or blind nerve** due to its **tortuous path** designed to extend its distance from the brain, - Gains **firmness and independence** before exiting, - Joins the **third pair**, distributing fibers to: - The **cheeks** and **broad facial muscles**, - **Temporal muscles**, - Muscles around the **ears** in animals.   #### **Remaining Cranial Nerves** **Sixth Pair:** - Originates from the **junction** of the **brain and spinal cord (medulla)**. - Primarily serves the **muscles that move the tongue**, - Also innervates the **muscles connecting the thyroid cartilage and the hyoid bone**. - Some of its fibers may extend into **adjacent muscles**, though not consistently. Because the **other cranial nerves** are committed to **other functions**, and because **additional foramina** in the anterior or lower parts of the skull would be impractical, **Tongue movement** is assigned to this pair — its **sensation** already comes from another nerve.   #### **Cervical Spinal Nerves (Neck Nerves)** There are **eight pairs** of cervical spinal nerves that originate from the **spinal cord** and exit between the **cervical vertebrae**: **First Pair:** - Exits through the **foramen of the first vertebra**, - Innervates the **muscles of the head only**, - It is **small and delicate**, since a narrow exit is required at that location. **Second Pair:** - Exits between the **first and second vertebrae**, - Most fibers **ascend obliquely**, giving **touch sensation to the head**, - Extends to the **external layer near the ears**, - Compensates for the **first pair’s small size and limited reach**, - Also innervates: - **Posterior neck muscles**, - The **broad trapezius muscle**, - And provides **motor power**. **Third Pair:** - Originates between the **second and third vertebrae**, - Each branch divides into two: - One supplies the **deep neck muscles**, especially those involved in **head and neck rotation**, - Extends to the **spinal processes** and their ligaments, - Wraps toward the **ears**, and in animals, even **moves ear muscles**. - The other branch goes **forward** to the **broad neck muscles**, - Twines with veins and muscles for added strength, - May also connect with **temporal** and **auricular muscles**, especially in animals, - Mainly spreads into **cheek muscles**. **Fourth Pair:** - Exits between the **third and fourth vertebrae**, - Also divides into anterior and posterior branches: - The **anterior part is small**, often fuses with the **fifth**, - One fiber may resemble a **spiderweb**, running along the **carotid artery** toward the **diaphragm**, - The **larger posterior part** dives deep into **posterior neck muscles**, sending: - Two branches to muscles shared by the **head and neck**, - One anterior branch connecting to **cheek and ear muscles** in animals, - It may also descend toward the **lower back**. **Fifth Pair:** - Originates between the **fourth and fifth vertebrae**, - Divides into: - An **anterior smaller branch** serving the **cheeks** and **head-lowering muscles**, - A second branch which: - Further splits: - One sub-branch ascends toward the **shoulder**, merging with the **sixth and seventh pairs**, - The other merges with **fifth–sixth–seventh pairs**, entering the **diaphragm**. **Sixth, Seventh, and Eighth Pairs:** - Exit successively through the **lower vertebral foramina**, - The **eighth pair** exits at the junction of the **last cervical and first thoracic vertebrae**. They form a **complex nerve network**, but in general: - The **sixth pair** mostly reaches the **shoulder surface**, - A portion joins with fourth and fifth fibers to serve the **diaphragm**, - The **seventh** mainly reaches the **upper arm**, though some fibers still go to the: - **Neck**, **head**, **spine**, and **diaphragm**. - The **eighth**, after merging with early thoracic nerves, innervates the **forearm and arm skin**. None of the **eighth pair** fibers serve the diaphragm; those that do are rerouted from higher pairs.   #### **Thoracic Spinal Nerves (****أعصاب فقار الصدر****)** **First Thoracic Pair:** - Exits between the **first and second thoracic vertebrae**. - Divides into two parts: - The **larger branch** innervates: - **Intercostal muscles** (between the ribs), - **Spinal muscles**. - The **smaller branch** extends along the **first rib**, - Joins with the **eighth cervical nerve**, - Together, they descend into the **arms**, reaching the **forearm and wrist**. **Second Thoracic Pair:** - Emerges from the next thoracic foramen. - One branch serves the **outer upper arm skin** (sensory). - Remaining fibers merge with the general thoracic nerve group, - Distribute to: - **Shoulder muscles**, - **Spinal muscles**. **All thoracic spinal nerves**: - If they do not go to the shoulder, they: - Supply the **intercostal muscles**, - The **outer chest muscles**, - Or descend toward the **abdominal muscles**. **Those originating from the rib-bearing thoracic vertebrae**: - Focus on **intercostal muscles** and **abdominal muscles**. Blood vessels: - Arteries (pulsating) and veins (non-pulsating) run alongside these nerves and enter the spinal cord through their foramina.   **Lumbar (Cotton) Nerves (****أعصاب القطن****)** - Serve **three primary zones**: - **Spinal muscles**, - **Abdominal muscles**, - **Muscles lining the lower spine** (deep stabilizers). - The **upper three lumbar pairs** often merge with **descending cranial nerves**, unlike the lower two. - **Lower two lumbar pairs**: - Send **large branches** toward the **legs**, - Also receive fibers from: - The **third lumbar pair**, and - The **first sacral nerve**. The branches destined for the **thighs and legs** are distinct from those of the arms: - They **do not merge fully** into a single trunk. - Instead, they branch and weave through **muscle layers** — some travel deep, some superficial, others under muscle. For **muscles arising near the pubic bone**: - Since **direct routes** to the **posterior thighs** or **inner thighs** are blocked by thick muscle and blood vessels, - Some lumbar branches reroute: - Pass through the **inguinal canal** (testicular path), - Reach **pubic muscles**, - Then descend to the **knee muscles**.   #### **Sacral Nerves (****أعصاب العجز****)** **First Sacral Pair:** - Merges with **lumbar nerves** (especially the lowest lumbar) as noted. **Remaining Sacral Nerves:** - Plus the **single coccygeal nerve** from the **tailbone**, - Spread into: - **Gluteal muscles**, - The **penis** itself, - **Bladder muscles**, - **Uterus** (in women), - **Abdominal lining**, - Inner pelvic bones, - Muscles arising from the **sacrum**. --- **Section:** ### **Arteries (****الشرايين****)** **General Characteristics:** - Arteries (العروق الضوارب) are **vessels that pulse**. - All arteries, **except one**, are composed of **two layers** (صفاقين): - The **inner membrane** is the **tougher** one. - It is designed this way to withstand the **force of the pulsation** and **preserve the essence** (جوهر) of the vital spirit (الروح). **Origin of Arteries:** - All arteries originate from the **left chamber** of the heart (**التجويف الأيسر**). - This is because: - The **right chamber** is closer to the **liver**, and thus primarily serves in **drawing nourishment** and processing it. - The **left chamber**, being more distant, is tasked with **distributing the refined spirit** throughout the body via arteries. **Chapter Two: Initial Arterial Branches** Two arteries first emerge from the **left heart chamber**: 1. **The Pulmonary Artery (****الشريان الوريدي****):** - Goes directly to the **lungs**. - **Divides within the lungs**, serving two purposes: - Carries **air** for inhalation, - Delivers **blood** from the heart to **nourish the lung tissue**. - **Formed from the softest part** of the heart — especially where **veins enter**. - It has **only one membrane**, unlike other arteries. - This single membrane makes it: - More **flexible**, - Easier to **expand and contract**, - Better at **secreting** the fine, vaporous part of the blood appropriate for the lungs. This is why it's called the **"venous artery"** (الشريان الوريدي), because: - Though an artery in function, it behaves structurally like a **vein**. It doesn’t need extra thickness or strength like other arteries because: - The **lungs** are delicate and not subject to harsh friction, - Its location is close to the **heart**, so heat and processing reach it easily. 1. **The Great Artery (****الأورطي****– Aorta):** - This is the **larger** of the two arteries. - Aristotle calls it the **Aorta** (أورطي). - At its base, it sends off two initial branches: **First Branch:** - Encircles the **heart** and branches within it. **Second Branch:** - Encircles and distributes within the **right chamber** of the heart. After these two branches, the **aorta** divides into: - A **larger descending branch**, - A **smaller ascending branch**. - The descending one is larger because: - It supplies organs that are more **numerous** and **larger**, - Especially those located **below** the heart.   ##### **Structure of Arterial Membranes:** - The **aorta** has **three thick membranes** arranged from **inner to outer**. - If it had only one or two: - It wouldn’t function properly unless made much larger — which would hinder its movement. - If it had four: - They would be too thin and ineffective, or too large and narrow the passage. - The **pulmonary artery**, by contrast, has **two inner membranes**: - Its **function doesn't require** such tight sealing as the aorta, - Instead, it prioritizes **smoothness** to facilitate the flow of **vapor and blood** to the lungs.   **Chapter Three:** ### **The Descending Aorta and Its Branches** After the **aorta** sends its initial branches around the heart, it continues **downward** and distributes to the major **organs below the heart**. **Main Descending Trunk:** - Larger than the ascending branch, due to the **greater number and size** of organs it supplies. - Enclosed in **three robust layers**, to: - Withstand strong pulsation, - Maintain the strength of the vital spirit carried within. **Major Arterial Branches Below the Heart:** 1. **Coronary Branches** (around the heart): - Already described: one wraps the heart itself; the other goes to the right heart chamber. 2. **Thoracic Branches**: - As it travels through the **chest**, the aorta sends small branches to: - The **pericardium**, - The **bronchi**, - The **esophagus**, - The **intercostal spaces** (between the ribs), - The **muscles of the thorax**. 3. **Diaphragmatic Branches**: - As it crosses the **diaphragm** (الحجاب الحاجز), it sends arteries to its muscular fibers and membranes. 4. **Abdominal Branches**: - Upon passing into the **abdominal cavity**, the aorta gives rise to: - The **celiac trunk**, supplying the: - **Stomach**, - **Liver**, - **Spleen**, - The **superior mesenteric artery**: - Supplies most of the **small intestine** and part of the **large intestine**, - The **renal arteries**: - Supply the **kidneys**, - The **gonadal arteries**: - Supply the **testicles** or **ovaries**, - The **inferior mesenteric artery**: - Supplies the **distal colon** and **rectum**. 5. **Terminal Bifurcation**: - As it nears the pelvis, the aorta **divides** into: - **Two common iliac arteries**, which further divide to supply: - The **pelvis**, - The **lower limbs**.   Each branch is shaped, layered, and directed according to the **function** and **resistance** of the organs it serves: - Softer organs require **finer**, more **delicate** arteries, - Muscular or dense organs are supplied by **thicker**, more **forceful** vessels. **Chapter Four: Description of the Veins (****الأوردة****)** **General Characteristics:** - Veins are **vessels that carry blood back** toward the heart. - Their function complements that of arteries, yet differs in **structure** and **purpose**. - Unlike arteries, veins do **not pulse**, but they are vital in **returning blood**, especially after it has been used for nourishment and waste removal. **Structural Features:** - Veins are generally **thinner-walled** and **softer** than arteries. - They often have **valves** (not always mentioned in pre-modern texts), preventing the **backflow** of blood. - They are designed to: - **Carry spent blood** back to the heart, - **Receive** blood from all parts of the body, - And **pass it** to the liver or the heart directly depending on the organ.   #### **Main Origins of Veins:** Veins are said to originate primarily from **two major sources**: 1. **The Liver:** - According to classical medical theory (especially Galenic), most **nutritional veins** originate in the **liver**, since the liver is considered the **seat of blood formation**. - These veins **carry nourishment**: - From the digestive organs **to** the liver (via the **portal vein**), - Then **from the liver** to the rest of the body (via the **vena cava**). 1. **The Right Chamber of the Heart:** - Some veins (especially those associated with **vital functions**) originate from the **right side of the heart**. - This includes: - The **superior vena cava**, draining the upper body, - The **inferior vena cava**, draining the lower body.   #### **Major Veins Described:** 1. **Portal Vein (****الوريد الباب****):** - Collects blood from: - The **stomach**, - The **intestines**, - The **spleen**, - And carries it to the **liver**. - It is thick and strong due to: - The quantity of blood it carries, - The resistance it must overcome as it branches within the liver. 1. **Hepatic Veins:** - Arise within the **liver** and **drain** its contents toward the **vena cava**. 1. **Vena Cava:** - A major vein extending from the **lower abdomen** up to the **heart**. - Receives branches from: - The **kidneys**, - The **gonads** (testicles or ovaries), - The **lumbar region**, - The **legs** (via the **iliac veins**). 1. **Jugular Veins:** - Collect blood from the **head and brain**, - Drain into the **superior vena cava**.   #### **Function and Design:** - Veins are strategically shaped to **accommodate pressure** differences across the body. - Their walls are **less muscular** but more **distensible** than arteries. - The **placement** of veins alongside arteries allows: - A **warming effect** on the blood from arterial heat, - And a **balanced distribution** across organ systems.   **Chapter Five:** ### **Comparative Summary of Arteries and Veins** This chapter outlines the differences in **function**, **structure**, and **origin** between arteries (sharāyīn) and veins (awridah), according to classical anatomical theory.   1. #### **Functional Differences** - **Arteries (sharāyīn):** - Carry the *rū**ḥ* *ḥ**ayawānī* (vital spirit) and refined blood outward from the heart. - Their pulse is **active**, forceful, and coordinated with the **beating of the heart**. - They supply **organs** with energy and **vital warmth** necessary for life and function. - **Veins (awridah):** - Return the **used blood** back to the heart (and the liver, in classical theory). - Their flow is **passive**, relying on **muscle movement**, **valves**, and **suction** created by the heart’s movement. - They carry **nutritional substances** after digestion, especially via the *al-warīd al-bābī* (portal vein).   1. #### **Structural Distinctions** - **Arteries:** - Wall: **Thick**, **elastic**, and **multi-layered** to endure the strong force of the pulse. - Layers: Typically **three tunics**, each with a specific strength and purpose. - Lumen: **Narrower**, to increase pressure and regulate flow directionally. - **Veins:** - Wall: **Thinner** and **more compliant**, often with only **two tunics**. - Designed for **volume** rather than pressure. - May contain **valves** to prevent backflow, especially in the **limbs**.   1. #### **Origins and Circulatory Pathways** - **Arteries:** - Originate from the **left ventricle** of the heart (*al-jayb al-aysar*). - Main trunk: *al-sharāyīn al-awra**ṭ**ī* (the aorta). - Distribute to the **entire body**, from the **head** down to the **toes**. - **Veins:** - Some veins originate from the **liver**, particularly the *al-warīd al-bābī* system. - Others begin from the **right side of the heart** (*al-jayb al-ayman*). - Return flow from **peripheral organs** toward the **central core** of circulation.   1. #### **Connection and Balance** - The **interplay between arteries and veins** ensures a **balanced circulation** of both vital and nutritive fluids. - Arteries serve the role of **distribution** (tafrīq), while veins fulfill **collection and return** (jamʿ wa-ʿawdah). - The harmony between the two supports: - **Nourishment**, - **Vitality**, - **Homeostasis** of internal heat and moisture (*al-**ḥ**arārah wa al-rutūbah*).   **Conclusion** The anatomical system, as described, reflects a **designed correspondence** between: - The **heart and liver** as dual centers, - The **arterial and venous trees** as complementary systems, - And the **upper and lower body**, **right and left sides**, **inner and outer organs**. This concludes the anatomical overview of: - The **muscles**, - The **bones**, - The **nerves** (especially cranial and spinal), - The **arteries**, - And the **veins**—according to the classical Greco-Islamic medical tradition.   **Chapter Three:** ### **Anatomy of the Ascending Aorta (al-sharāyīn al-****ʿ****awra****ṭ****ī al-ṣā****ʿ****id)** The **ascending portion** of the aorta divides into two parts. The **larger part** ascends toward the **gingiva** (al-litha), then inclines to the **right side** until it reaches the **soft connective tissue** (al-laḥm al-rakhw al-tawthī) in that region. There it divides into **three branches**: 1. **Two of them** are the arteries known as the **carotid arteries** (*al-sharāyīn al-sabātiyyayn*), ascending to the right and left, accompanied by the **deep jugular veins** (*al-awdaj al-ghā**ʾ**ir*) which will be described later, and they divide in the same manner. 2. The **third branch** is distributed to the **trachea** (*al-qaṣaba*), the **first true ribs**, the **upper six vertebrae of the neck**, and the **area around the clavicle** until it reaches the **shoulder joint**, and then extends beyond it to the **arms**. The **smaller part** of the ascending aorta extends toward the **armpit** (*al-ib**ṭ*), where it divides like the third branch of the larger part.   **Chapter Four:** ### **Anatomy of the Carotid Arteries** Each of the **carotid arteries** (*al-sabātiyyān*) divides at the **neck** into two parts: - A **front branch** and a **back branch**. **The anterior branch:** - Divides into: - One part that goes **inward** to supply the **tongue** and the **internal muscles** of the lower jaw. - Another part that goes **outward**, ascending in front of the **ears**, supplying the **temporal muscles**, then branching into many smaller vessels to the **crown of the head**, where the **right and left sides** eventually meet. **The posterior branch:** - Divides into two: - The **smaller portion** ascends toward the **back of the head**, spreading through the **muscles surrounding the head joint**, with some parts directed to the **base of the posterior brain**, entering through a **large foramen** near the **lambdoid suture** (*al-darz al-lāmī*). - The **larger portion** enters through the **foramen in the petrous bone** (*al-**ʿ**a**ẓ**m al-**ḥ**ijrī*) into the **rete mirabile** (*al-shabaka*). From it, a network of vessels is formed, layer upon layer, interwoven in such a way that no single vessel can be isolated without being connected to another—just like a **net**. This **network** spreads **forward, backward, right and left**, and then **reconverges** into a pair of vessels. A **membrane** is perforated for them, allowing the flow to ascend into the **brain**. There, it spreads into the **delicate meninges** and through them into the **brain tissue**, filling the **ventricles** and their linings. It meets the **openings of branches** that had ascended, and also the **openings of descending venous branches**.   #### **Rete Mirabile and Cerebral Circulation** The blood passing through the **rete mirabile** (al-shabaka) gradually adapts to the **temperament of the brain** (mizāj al-dimāgh) after **cooking** or refinement (*n**ض**uj*). Then it **passes gradually** into the brain. The **rete** is located **beneath** the brain so that the **arterial blood and vital spirit** (al-rūḥ) flowing through it can **temper** and warm before being transmitted into the cerebral tissue. From the **rete**, the flow enters the **thin meningeal layer** (al-ghishāʾ al-raqīq), and from there, **spreads throughout the brain** into its **substance** and **ventricles**, and lines their walls. It also reaches the **mouths** of **arterial and venous branches** that either **ascended** or **descended**, coordinating the in- and out-flow. - The **descending venous branches** (*al-**ʿ**ur**ū**q al-war**ī**diyya al-n**ā**zila*) drain the blood, - The **ascending arterial branches** bring **vital spirit**. The **directionality** of flow is deliberate: - The **ascending vessels** are upright to ease the **ascent of the rū****ḥ**, which is **light** and **mobile**. - If these vessels were reversed, it would cause **excessive loss of blood**, which accompanies the rūḥ, and would hinder its motion. - The **descent of blood** is suited for drainage, - But the **ascent of rū****ḥ** is easier and more natural in upright vessels. The **fine and mobile nature** of the rūḥ is sufficient for it to **diffuse throughout the brain**, supplying what it needs and providing warmth.   **Chapter Five:** ### **Anatomy of the Descending Aorta (al-sharāyīn al-nāzil)** The **descending part** of the aorta travels **straight downward** until it reaches the **fifth vertebra**, which lies directly beneath the **heart**, supported by **connective tissue** (*tawtha*) acting as a cushion between it and the **spinal bones** and **esophagus**. At this point: - The aorta **deviates slightly to the right**, - Then continues **independently**, supported by **membranes** to avoid **compression** at the diaphragm (*al-**ḥ**ijāb*). From here, it **descends further**, continuing **along the spine** to reach the **sacrum** (*ʿ**a**ẓ**m al-**ʿ**ajz*).   #### **Branches Along the Thorax and Abdomen** As it descends, it gives rise to: - A **small branch** to the **lung** (*al-ri**ʾ**a*), which reaches the **bronchi**. - One branch for **each vertebra**, reaching: - The **intercostal spaces** (*bayn al-a**ḍ**lā**ʿ*), - And the **spinal cord** (*al-nukhā**ʿ*). Once it passes the **chest**, it gives off: - **Two arteries** to the **diaphragm**, spreading right and left. - A large **branch** with multiple divisions to the: - **Stomach** (*al-mi**ʿ**da*), - **Liver** (*al-kabid*), - **Spleen** (*al-**ṭ**i**ḥ**āl*). From the **liver**, a branch continues to the **bladder** (*al-mithāna*). Then, a branch reaches the **intestinal mesentery** surrounding: - The **jejunum** (*al-am**ʿ**ā**ʾ**al-diq**ā**q*), - And the **colon** (*qūlūn*). #### **Renal and Gonadal Branches** Three **renal branches** emerge: - The **smallest** supplies the **left kidney**, nourishing its tissue and surroundings. - The **other two** go to both kidneys, drawing **impure blood** for filtration. From there: - Two arteries descend to the **gonads** (*al-unthayyayn*): - The one to the **left** often arises from the **left renal artery**, - The one to the **right** typically comes from the **main aorta**, but may occasionally accompany the **right renal artery**.   #### **Terminal Division of the Aorta and Its Branches** As the **great descending artery** (*al-sharīān al-kabīr*) reaches the **end of the spinal column**, it **divides** together with the **accompanying vein** (*al-warīd al-ṣā**ḥ**ib*) into **two branches**, in the **shape of the Greek letter lambda (Λ)**: - One branch turns **rightward** (*yatyāman*), - The other **leftward** (*yatyāsar*). Each of these two **iliac arteries** then travels along the **sacrum** (*ʿ**a**ẓ**m al-**ʿ**ajz*), proceeding toward the **thighs**. Before reaching the thighs, each gives off: - A **vein** directed to the **bladder** (*al-mithāna*) and to the **umbilicus** (*al-surra*), - These two **meet at the umbilicus**, and are **clearly visible in the fetus** (*al-ajinna*). In **fully developed bodies**, the **ends** of these fetal veins **dry up**, but their **roots remain** and give rise to **branches** that spread across the **muscles overlying the sacrum**. From these branches: - Some supply the **bladder**, and divide within it. - Some reach the **tip of the penis** (*al-qa**ḍ**īb*) in men, and the **uterus** (*al-ra**ḥ**im*) in women — both from a **small paired artery**.   #### **Arterial Supply to the Lower Limbs** The **two descending branches** to the **legs** divide in the **thighs** into: - A **lateral branch** (*wa**ḥ**shī*), - And a **medial branch** (*insī*), - Though even the lateral branch tends to **veer medially**. The lateral branch gives off: - Arteries to the **muscles in the thigh**, - Then curves forward, sending a **large artery** between the **big toe** (*al-ibham*) and the **second toe** (*al-sabāba*), - The rest of it travels deep inside the **leg**, beneath the **venous branches** (to be described later), continuing its course **underneath** to supply the **largest portion of the leg**.   #### **Notable Correlations Between Arteries and Veins** Some **arteries align with veins**, such as: - The one that travels from the **liver to the umbilicus** in fetuses, - The arterial branches **aligned with venous paths**, - The artery that penetrates the **fifth vertebra**, - The one ascending to the **groin** (*al-labba*), - The one directed toward the **armpit** (*al-ib**ṭ*), - The **carotids** (*al-sabātiyyān*) as they split and spread into the **rete mirabile** and **placenta**, - Those that reach the **diaphragm** (*al-**ḥ**ijāb*), - And those that pass to the **shoulder** along with smaller branches, - Also, those that reach the **stomach**, **liver**, **spleen**, and **intestines**. Other arteries: - Descend from the **flanks of the abdomen**, - Or follow the **veins embedded in the sacral bone**.   #### **Spatial Relationships of Arteries and Veins** - When arteries run alongside muscles situated **over veins**, the **artery rides the vein**, being the **nobler vessel**. - In **external organs**, the **artery lies deeper**, beneath the **vein**, making it **better hidden and protected**, with the vein acting as a **cover** or **shield**. The **arteries accompany veins** for two reasons: 1. So that **veins** connect with the **membranes** surrounding the **arteries**, drawing nourishment from **shared surroundings**, 2. And so that **each vessel can nourish the other**, with **mutual exchange**. --- **Chapter One:** ### **Description of the Veins (ṣifat al-****ʿ****ur****ū****q)** The **stationary veins** (*al-**ʿ**ur**ū**q al-s**ā**kina*) all originate from the **liver** (*al-kabid*), which serves as their common source. From the liver, two primary veins arise: 1. From the **concave side** (*al-jānib al-mu**ʿ**taṣir*), emerges the vein known as the **portal vein** (*al-bāb*). - Its principal function is to **draw in nourishment** from the digestive tract **into the liver**. 2. From the **convex side** (*al-jānib al-muta**ḥ**addib*), emerges the **vena cava** (*al-ajwaf*). - Its function is to **distribute nourishment from the liver to the rest of the body**.   **Chapter Two:** ### **Anatomy of the Portal Vein (al-bāb)** Let us begin with the **dissection of the portal vein** (*al-**ʿ**irq al-musamm**ā**bil-b**ā**b*). This vein, upon entering the **depths of the liver**, **divides into five branches**, which spread out until they reach the **convex surface** of the liver. From these branches: - One vein extends to the **gallbladder** (*al-mirāra*). These branches resemble the **roots of a tree** plunging toward the depth of their source. On the **outer portion** of the portal vein: - A **small branch** connects directly to the **duodenum** (*al-mi**ʿ**ā**al-musamm**ā**ithnay**ʿ**ashar*), drawing nourishment from it. - Sometimes, additional small branches diverge toward the **pancreas** (*al-jaram al-musammā bānqirās*). Another **division** extends to: - The **lower part of the stomach** (*asāfil al-mi**ʿ**da*), especially near the **pylorus** (*bawwāb al-mi**ʿ**da*), to draw in partially digested food.   #### **Other Portal Branches** Among the **remaining six branches**, we find: 1. One ascends to the **outer left side** of the stomach to nourish its surface. - Since the **inner side** of the stomach is already in contact with food, it receives nourishment directly by **absorption**. 2. A second branch travels to the **spleen** (*al-**ṭ**i**ḥ**āl*), nourishing it. - Before reaching the spleen, it sends off small branches to the **pancreas**, delivering purified blood. - Once it connects to the spleen, another **significant branch loops back** toward the **left side of the stomach** to nourish it as well. 3. From within the spleen: - One portion of the branch travels **upward**, supplying the **upper half** of the spleen, - Another portion descends and reaches the **greater curvature** of the stomach (*ḥ**udbat al-mi**ʿ**da*), - This latter splits into: - A branch that spreads on the **outer left** of the stomach, - And one that enters the **pyloric region** to **stimulate appetite** by irritating the surface — as discussed earlier. 4. The **descending portion** of the same branch divides: - One part supplies the **lower half** of the spleen, - The other reaches the **omentum** (*al-thirb*) and branches within it to nourish it. 5. A **third portal branch** proceeds to the **left side**, distributing itself among the **mesenteric veins** surrounding the **rectum**, helping absorb **heavy remnants** of digested food. 6. A **fourth branch** splits finely, with: - One division toward the **right side** of the stomach, - Another toward the **right side** of the omentum — both matching their counterparts from the spleen side. 7. The **fifth branch** targets the **mesenteric vessels around the colon** (*ma**ʿ**ī**q**ū**l**ū**n*), assisting in absorption. 8. The **sixth** is mostly distributed around the **jejunum** (*al-ṣā**ʾ**im*) and parts of the **ileum** (*al-lifā**ʾ**if al-daq**ī**qa*) attached to the **cecum** (*al-a**ʿ**war*), drawing out nourishment.   **Chapter Three:** ### **Anatomy of the Vena Cava (al-ajwaf) and Its Ascending Branches** The **vena cava** (*al-ajwaf*) originates in the **liver**, where it divides into numerous **fine branches** (like threads), drawing nourishment from the **capillaries of the portal vein**, which are themselves threadlike. - The **branches of the vena cava** penetrate the liver **from its convex surface** (*ḥ**adabat al-kabid*), - While the **branches of the portal vein** enter **from its concave surface** (*taqa**ʿ**ur al-kabid*), - Both sets of branches converge within the **interior of the liver** (*jawf al-kabid*). From there, the **main trunk** of the vena cava emerges from the **convex side**, and it divides into: 1. An **ascending branch** (*ṣā**ʿ**id*), 2. A **descending branch** (*hābi**ṭ*).   #### **The Ascending Branch** - Passes through the **diaphragm** (*al-**ḥ**ijāb*) and penetrates it, - Leaves behind **two veins** that spread through the **diaphragm**, supplying it with nourishment. Then it runs alongside the **pericardium** (*ghilāf al-qalb*) and sends a **large branch** into it. - From this large branch, a particularly **significant vein** reaches the **heart**, entering it near the **right auricle** (*udhn al-qalb al-ayman*). This vein is considered the **greatest vein of the heart**, because: - Other veins are meant to carry **pneuma** (*nasīm*), - But this one delivers **nourishment**, which is **thicker** than pneuma, - Hence it requires a **larger channel** and **wider vessel**. Upon entering the **heart**, this vein becomes enclosed within **three membranes**: - With an inner and outer lining, - Allowing the **heart to draw nourishment** during its **diastole** (expansion), - But preventing it from flowing back during **systole** (contraction), - These membranes are the **firmest** of all bodily sheaths.   #### **Veins to the Lungs and Pulmonary Circulation** From the vena cava, near the heart, arise **three veins**: - These pass into the **lungs**, protruding near the **left pulmonary artery** (*al-sharāyīn al-ayman*), - They loop back through the **right atrial chamber** to the **lungs**. These veins are: - **Wrapped in two sheaths**, just like arteries, - For this reason, they are referred to as **arterial veins** (*al-warīd al-sharīānī*). Their **main purpose** is to deliver **refined blood** — extremely thin and compatible with the **substance of the lungs**, because this blood is **fresh from the heart**, not yet fully cooked like the blood found in the **pulmonary arteries**.   **Chapter Three (continued): The Descending Branch of the Vena Cava (al-ajwaf)** After describing the **ascending branch**, we now turn to the **descending course** of the **vena cava**, which: - Moves **downward** after leaving the **liver**, toward the **lower parts of the body**, - Accompanied and encased in membranes to maintain **protection** and **support**. As it descends, it gives rise to **multiple branches**, serving various **vital organs**, including:   #### **Branches to the Kidneys and Urinary System** - **Two large veins** branch off to supply the **kidneys** (*al-kuliyatayn*), one on each side. - These **renal veins** serve to: - **Extract aqueous waste** (*mā**ʾ**iyyat al-dam*) from the blood, - This waste is then **urinated**. Ibn Sīnā notes that these veins often **draw impure blood** from the **stomach and intestines** along with the cleaner portions.   #### **Branches to the Bladder and Genital Organs** - Two **additional veins** extend toward the **reproductive organs** (*al-unthayyayn*): - The vein going to the **left side** often shares a **common origin** with the **left renal vein**, - Sometimes it arises **solely** from the **left kidney**. - The vein to the **right reproductive organ** arises directly from the **main trunk of the vena cava**, - But occasionally draws from the **right kidney** as well. - These branches eventually **supply the bladder**, the **genitalia**, and in females, the **uterus** (*al-ra**ḥ**im*), - In males, the vein reaches the **tip of the penis** (*a**ṭ**rāf al-qa**ḍ**īb*), - In females, the paired vein supplies the **womb**.   #### **Division of the Vena Cava at the Sacrum** When the **vena cava** reaches the **lower end of the spinal column**, it **bifurcates** just like the **aorta**, into: - A **right** and a **left** branch, following a path **along the sacrum** (*ʿ**a**ẓ**m al-**ʿ**ajz*), - Each descends into the **thighs**, where they give off: - **Lateral and medial branches**, supplying **muscles**, - **Branches to the bladder**, **umbilicus**, and **lower abdominal wall**. In **fetuses**, these veins are prominent and meet visibly at the **navel**, whereas in **fully developed adults**, the **ends are dried**, but the **roots remain functional**, supporting: - **Pelvic muscles**, - **External genitalia**, and - **Urinary and reproductive functions**. As each **branch** of the bifurcated **vena cava** enters the **legs**, it: - Divides into two **major branches**: - One **lateral** (*wa**ḥ**shī*), - One **medial** (*insī*). The **lateral branch** has a **slight inclination** toward the **medial side**, ensuring overlap and continuity. Along its path, it sends off: - Multiple **branches to the muscles** of the thigh and leg. From the **medial side**, a **major vein** extends downward between the **big toe** and the **second toe**, continuing deep into the foot. These veins mirror the distribution of **major arteries** (as mentioned previously), but unlike arteries, veins tend to lie **closer to the surface** in the **visible parts of the body**, and **beneath the arteries** in the **internal regions**.   **Venous-Arterial Correspondence and Functional Integration** - In the **abdomen**, where arteries and veins run together: - The **vein often rides atop the artery** (*yamta**ṭ**ī al-sharīān*), - The **lesser** (vein) **carrying** the **greater** (artery), - In the **visible parts** of the body: - The **vein is deeper**, while the **artery is more superficial**, - Providing **concealment** and **protection**. This spatial configuration is not arbitrary: - The **artery** brings **life-giving heat and pneuma**, - The **vein** brings **cooler nourishment**. Each pair: - Is joined to allow **mutual interaction**, - So that each vessel may **absorb what it needs** from the other, - And to serve **adjacent organs** more effectively. ---   ### **Fifth Summary (al-Jumla al-Khāmisa)** **Chapter Four:** ### **Paired Structure and Functions of Veins and Arteries** Ibn Sīnā emphasizes that **arteries** (*ḍ**awārib*) and **veins** (*ʿ**urūq*) often run in parallel, and their paths overlap for specific reasons — both **functional** and **structural**. #### **Key Examples of Artery-Vein Pairings:** - The **vein extending from the liver to the umbilicus** (*al-surra*) in fetuses parallels an **arterial counterpart**, - Veins and arteries ascend together to: - The **fifth vertebra**, - The **base of the neck** (*al-lubba*), - The **armpit** (*al-ib**ṭ*), - The **carotid arteries** (*al-sabātiyyayn*) and their spreading branches into the **rete mirabile** (*al-shabaka*) and the **placenta** (*al-mashīma*), - The **diaphragm**, **shoulders**, **stomach**, **liver**, **spleen**, **intestines**, and **lower abdomen**, - As well as the **sacral veins** (*ʿ**urūq**ʿ**a**ẓ**m al-**ʿ**ajz*). Wherever veins and arteries **run together**, one generally serves to **carry blood**, the other **pneuma** or **nourishment**. They accompany each other so that: 1. **Membranes of the artery** provide structural support to the **vein**, 2. Organs between them **receive nourishment or warmth**, 3. Each vessel may **draw from or give to the other**, depending on **need**.   #### **Spatial Hierarchies Between Arteries and Veins** - In **internal organs**, **veins ride atop arteries** to maintain a **hierarchical structure**: - The **lesser** carries the **nobler** — metaphorically and anatomically. - In **visible or external organs**, **arteries lie beneath veins**: - This protects the artery from **external trauma**, - The **vein acts as a shield** — a kind of **armor** (*junnah*).   #### **Why Arteries Are Accompanied by Veins** Ibn Sīnā gives **two key reasons**: 1. **Anchorage and Stability**: - The **veins attach** to the **sheaths of the arteries**, - This provides anatomical **anchoring** and ensures that they can **draw from nearby organs**. 2. **Functional Synergy**: - Each vessel can **exchange material** with its partner, - Ensuring **efficiency** in delivery and regulation of **blood**, **pneuma**, and **heat**. --- **Fifth Summary (al-Jumla al-Khāmisa)** **Chapter Five:** ### **The Veins — An Overview of the Five Principal Categories** Ibn Sīnā classifies **veins** (*al-**ʿ**ur**ū**q*) into **five primary types**, each with unique anatomical origins, pathways, and functions. These are discussed across five chapters.   **Chapter One:** ### **Description of the Veins** All **stationary veins** (*al-**ʿ**ur**ū**q al-s**ā**kina*) originate in the **liver**, and from there distribute nourishment throughout the body. The **first two veins** to arise from the liver are: 1. **The Portal Vein (al-bāb)** - Arises from the **concave side** (*al-jānib al-mun**ḥ**anī*) of the liver. - Its **main function** is to **draw nutrients** into the liver from the intestines and digestive tract. 2. **The Vena Cava (al-ajwaf)** - Arises from the **convex side** (*al-jānib al-mutakabbir*) of the liver. - Its **main function** is to **carry nourishment** outward from the liver to all other organs.   **Chapter Two:** ### **Anatomy of the Portal Vein (al-bāb)** The **portal vein** has two ends: 1. #### **The Deep (Liver-facing) End:** - This end divides into **five main branches** within the **liver’s interior** (*jawf al-kabid*), - These branch further until they reach the **convex surface** of the liver, - One branch proceeds to the **gallbladder** (*al-marrāra*). Ibn Sīnā likens these branches to the **roots of a tree**, anchoring deeply into the organ to supply it from within. 1. #### **The Outer End (toward the digestive organs):** This outer end splits into: - A **small branch** connecting directly to the **duodenum** (*al-mi**ʿ**ā**al-musamm**ā**ithnay**ʿ**ashar*), - It draws nutrients directly from there. - A **second branch** spreads through the **lower part of the stomach**, particularly near the **pyloric orifice** (*bawwāb al-mi**ʿ**da*).   The remaining **six branches** serve the following: - One reaches the **flat (external) side** of the stomach to **nourish its outer layers**, - Since the **inner lining** of the stomach is nourished by **direct contact with food**. - Another goes to the **spleen** (*al-**ṭ**i**ḥ**āl*), and before it arrives, gives off several **small branches** that: - Nourish the organ called **banqarās** (likely the pancreas) with **refined material**, - Then, upon reaching the spleen, a return branch proceeds to **nourish the left side** of the stomach. Ibn Sīnā notes a **looping structure**: blood flows **into** the spleen, and **back out** to nourish other parts — a sort of **recirculating support system**. 1. **Third Branch** - Extends to the **left side of the abdomen** (*al-jānib al-aysar*), - Divides into small veins around the **rectum** (*al-ma**ʿ**ī**al-mustaq**ī**m*), - Its role is to **absorb the remaining heaviness** (*al-thiql*) of what is left from digested food. 1. **Fourth Branch** - Divides like fine **threads** (*ka-l-sha**ʿ**r*), - Some spread along the **right outer side of the stomach**, - Opposite the **left-sided branches** that come from the spleen. - Others head toward the **right part of the omentum** (*al-thirb*), - To nourish it directly, in balance with what the **left portal branches** provide. 1. **Fifth Branch** - Spreads through the **networks of veins** that surround the **colon (qūlūn)**, - For **final-stage nutrient absorption**. 1. **Sixth Branch** - Primarily nourishes the **jejunum** (*al-ṣā**ʾ**im*) and partially the **ileum** (*al-lifāf al-daqīqa*), - Which connect to the **cecum** (*al-a**ʿ**w**ā**r*), - Draws nutrients from **undigested remnants**, especially fluids. Ibn Sīnā concludes this chapter by reiterating the **precision** of the portal vein’s distribution and the **delicate layering** of its branches, tailored to the absorption capacities of each intestinal section. --- **Fifth Summary (al-Jumla al-Khāmisa)** **Chapter Three:** ### **Anatomy of the Vena Cava (al-ajwaf) and Its Ascending Branches** The **vena cava (al-ajwaf)** begins within the **liver**, dividing into **fine capillary-like branches** (*ka-l-sha**ʿ**r*) that: - Draw **nourishment** from the **portal vein’s branches**, - Particularly from the **rounded convex side** (*ḥ**adabat al-kabid*) of the liver, flowing **inward**. Meanwhile, the **branches of the portal vein** move **from the concave side** (*taqa**ʿ**ur al-kabid*) inward as well. Once these **internal pathways** are completed, the **main stem** (*sāq*) of the **vena cava** rises at the **rounded edge of the liver** and splits into **two directions**:   #### **Ascending Branch of the Vena Cava** - This **ascending part** **pierces the diaphragm** (*al-**ḥ**ijāb*), - Leaving two **small veins** that branch into and nourish the diaphragm itself. - As it reaches the **pericardium** (*ghilāf al-qalb*), it sends out **a large branch** that: - **Divides** again, one part going to the **heart** (*al-qalb*), - Penetrates the **right atrium** (*udhn al-qalb al-ayman*). Ibn Sīnā calls this branch **the greatest of all heart veins**. #### **Why Is This Heart Vein the Greatest?** - Because **other vessels** serve the **inhalation of air** (*al-nasīm*), - But **this vein serves nourishment** (*al-ghidhā**ʾ*), - Which is **denser and more substantial** than air, - Requiring a **larger conduit** and **wider mouth**. This vein is covered with **three membranes**: - Layered **from inside out and outside in**, - So that the **heart can draw nourishment** efficiently during its **expansion** phase, - Preventing backflow upon **contraction**. The membranes are described as the **toughest** of all, due to the **intense movement and heat** of the heart.   #### **Branches from the Vena Cava to the Lungs** As the **ascending vena cava** passes by the **heart**, it releases **three branches** toward the **lungs**, near the **left side** (*bi-qurb al-aysar*), and these: - Project **upward** where the **arteries** are situated (*ʿ**inda maniyat al-sharāyīn*), - Then bend **into the right chamber** of the heart (*al-tajwīf al-ayman*) and from there into the **lungs**. These vessels are covered by **two sheaths**, just like arteries, and are therefore referred to as: **"Vein-arteries" (al-****ʿ****irq al-shar****īā****n****ī****)"** — because they are **veins in function** but **share structural features** with **arteries**, such as: - **Thicker walls**, - **Greater elasticity**, - A role in **transmitting refined blood**.   #### **The Purpose of This Dual Structure** The **first benefit** of this vein-artery dual structure is: - To allow **blood that filters through it** to be **extremely refined** (*fī ghāyat al-raqqa*), - This ensures it matches the **nature of the lung**, which is a **delicate, spongy organ**. Additionally: - This blood is **fresh from the heart**, - Not yet fully “cooked” or transformed as it is in the **arterial system**, - Making it ideal for **gas exchange** and **further refinement** in the lungs. --- **Fifth Summary (al-Jumla al-Khāmisa)** ### **The Descending Branch of the Vena Cava (al-ajwaf al-hābi****ṭ****)** After supplying the heart and lungs, the **vena cava** sends a **descending branch** downward through the **diaphragm** to serve the **abdomen and lower body**.   #### **Path and Branching of the Descending Vena Cava** - As it **passes downward**, it leaves: - **Branches to the stomach**, **liver**, and **spleen**, - One branch continues to the **bladder** (*al-mathāna*), - Another supplies the **mesenteric veins** (*judhūl al-**ʿ**ur**ū**q*) around the **small intestines** (*al-am**ʿ**ā**ʾ**al-diq**ā**q*) and the **colon** (*qūlūn*). Then it gives rise to **three more veins**: 1. **First of the Three** - Supplies the **left kidney** (*al-kulya al-yusrā*), - Spreads into its loops and surrounding tissues, - Provides **nourishment and vitality**. 1. **& 3. The Other Two** - Extend to the **right and left kidneys**, - Assist the kidneys in **drawing watery material** from the blood, - Especially useful in filtering **impure blood** that often comes from the **stomach and intestines**.   #### **Genital Veins (al-unthayyayn)** Two more veins split from the vena cava to reach the **genital organs**: - The one going to the **left testicle** (*al-khuṣya al-yusrā*) often originates from the **left kidney**, - Sometimes it's entirely derived from that kidney. - The one to the **right testicle** (*al-khuṣya al-yumnā*) always originates from the **main vena cava**, - Though occasionally it also receives a contribution from the **right kidney**. Ibn Sīnā highlights the **asymmetry** of origin in these genital veins.   #### **Lower Branching and Final Division** As the **vena cava** descends further, it gives rise to: - Veins around the **rectum** (*al-ma**ʿ**ī**al-mustaq**ī**m*), - Branches to the **spinal cord** (*al-nukhā**ʿ*), - Entering through the **vertebral foramina** (*thuqūb al-faqār*), - Veins to the **flanks** (*al-khāṣiratayn*), - And additional **genital branches**. A **small paired vein** then extends to the **external genitalia** (*al-qubul*), - This is **not the same** as the veins mentioned later in male and female anatomy, - It joins with **other veins**, forming part of the **networked venous system**.   #### **Terminal Bifurcation of the Vena Cava** When the **great vena cava (al-****ʿ****irq al-ajwaf al-kab****ī****r)** reaches the **end of the vertebral column** (*ākhir al-faqār*), it splits—along with its accompanying **vein**—into **two branches**, forming a **Y-shape** similar to the **Greek letter lambda (Λ)**: - One branch goes **rightward** (*yatīyāman*), - The other **leftward** (*yatīyāsar*), - Each descends to rest upon the **sacrum** (*ʿ**a**ẓ**m al-**ʿ**ajz*), - Then continues toward the **thighs** (*al-fakhdhayn*).   #### **Pelvic and Genital Branches** Before each branch reaches the thigh, it releases: - A **vein to the bladder** (*al-mathāna*), - A branch to the **navel** (*al-surra*). These two meet **at the navel** and are **especially visible in fetuses**. In **fully developed adults** (*al-mustakmilīn*): - The **ends of these fetal veins dry up**, - But their **roots remain**, from which emerge: - **Branches to the muscles** over the sacrum, - A branch to the **penis** in men (*al-qa**ḍ**īb*), - And a branch to the **uterus** in women (*al-ra**ḥ**im*), - Forming a **small paired vein** in each case.   #### **Veins to the Lower Limbs** As the **two vena cava branches** reach the **legs**, each divides into: - A **major outer branch** (*wa**ḥ**shiyy*) and - A **major inner branch** (*insiyy*). Even the **outer branch** tends to **lean inward**, and from it arise: - **Branches to the thigh muscles**, - A **large vein** moving forward between the **big toe and second toe**, - Running internally along the foot. This branch becomes the **main venous conduit of the leg**, lying beneath its **venous arches**, which Ibn Sīnā promises to describe next. Ibn Sīnā identifies several **critical "striking veins"** (*ḍ**awārib*) that align with arteries: - From the **liver to the navel** in fetuses, - At the fifth vertebra, - At the **shoulder**, **armpit**, and **neck** (including the carotids), - To the **lungs**, **diaphragm**, **spleen**, **intestines**, and **lower abdomen**, - And through the **sacrum**. In deeper structures: - The **artery rides above the vein**, since the **vein is considered more noble**, - And the artery is its **carrier**. In superficial structures: - The **artery sinks beneath the vein**, for **protection and concealment**, - The vein acts like a **shield**. --- **Fifth Summary (al-Jumla al-Khāmisa)** **Chapter Four:** ### **Anatomy of the Portal Vein (al-bāb)** Ibn Sīnā begins the dissection of the **vein known as al-bāb (the portal vein)** by noting that it is: “The first to branch within the liver,” Its function is to **draw nourishment (al-ghidhā****ʾ****)** from the **intestines** and **convey it to the liver**.   #### **Initial Branching of the Portal Vein Inside the Liver** The **deep end** (*ṭ**arafuhu al-ghā**ʾ**ir*) of the portal vein inside the liver divides into **five major branches**, which: - Spread throughout the liver, - Reach even its **convex (outer) surfaces**, - One branch continues to the **gallbladder** (*al-mirāra*). These branches act like **roots of a tree**, spreading inward toward their source of nourishment.   #### **External Division Toward Digestive Organs** The **external portion** (*ṭ**arafuhu al-**ẓ**āhir*) of the portal vein divides into **eight branches**: 1. **First Branch** - Connects directly to the **duodenum** (*al-mi**ʿ**ā**al-musamm**ā**ithnay**ʿ**ashar*), - Draws nourishment from it. - It also sends **tiny twigs** into the **pancreas** (*al-jirm al-musammā bānqrās*). 1. **Second Branch** - Reaches the **lower part of the stomach** (*asāfil al-mi**ʿ**da*), - Especially around the **pylorus** (*al-bawwāb*), - Draws semi-digested food for liver processing. 1. **Third Branch** - Spreads over the **outer surface of the stomach**, - Since the **inner surface** directly contacts food and absorbs by proximity, - The **outer surface** must be nourished separately. 1. **Fourth Branch** - Extends to the **spleen** (*al-**ṭ**i**ḥ**āl*), - Before reaching the spleen, it sends small branches to the **pancreas**, - Then connects to the spleen. - After entering the spleen, one branch **returns** from it, - This branch **splits** into further twigs, - One nourishes the **left side of the stomach**, - Others go to the **upper curve** (*ḥ**adbat al-mi**ʿ**da*), - Some reach its **left outer side**, - Others burrow inward to deliver **black bile (sawdā****ʾ****)** and **stimulate appetite**. 1. **Fifth Branch** - This branch extends toward the **left side** (*al-jānib al-aysar*), - It **branches into the venous loops** (*judhūl al-**ʿ**ur**ū**q*) surrounding the **rectum** (*al-ma**ʿ**ī**al-mustaq**ī**m*), - Its function is to **absorb the denser remnants** of nourishment from the lower digestive tract. 1. **Sixth Branch** - It splits into **two parts**: - One spreads through the **outer right side** of the **gastric curve** (*ḥ**adbat al-mi**ʿ**da*), - Facing the area served by the **fourth branch** on the left. - The second heads toward the **right omentum** (*thirb*) and disperses within it. 1. **Seventh Branch** - This one distributes through the **venous channels around the colon** (*ma**ʿ**ī**q**ū**l**ū**n*), - Assists in drawing **remaining nutrients** from the partially digested material. 1. **Eighth Branch** - Mostly branches around the **jejunum** (*al-ṣā**ʾ**im*), - And the **ileum** (*al-lafā**ʾ**if al-daq**ī**qa*) near the **cecum** (*al-a**ʿ**war*), - Draws what is **still nutritive** from this final stretch of the small intestine. Ibn Sīnā concludes: “Know this” (*fa**ʿ**lam dh**ā**lika*), signaling the closure of the complex vascular map of the **portal vein system**. --- **Fifth Summary (al-Jumla al-Khāmisa)** **Chapter Five:** ### **Anatomy of the Vena Cava (al-ajwaf) and Its Ascending Branches** Ibn Sīnā now turns to the **superior portion** of the **vena cava** (*al-ajwaf*), focusing on the **branches that ascend** from it toward the **thoracic cavity**, the **heart**, and **lungs**.   1. #### **Origin and Function** - The **root** of the vena cava begins within the **liver**, - There, it spreads like **hair-thin fibers** throughout the organ, - Its purpose: to **draw nutrients** from the **branches of the portal vein**, - Since the portal system delivers nourishment to the liver, - The vena cava collects **refined, filtered blood** from it. Ibn Sīnā notes the **anatomical difference**: - The **portal branches** (al-bāb) enter the liver from the **concave side** (*al-taq**ʿ**ī**r*), - While the **caval branches** (al-ajwaf) enter from the **convex side** (*al-**ḥ**udba*).   1. #### **Main Stem and Its Ascension** After collecting blood in the liver: - The **trunk of the vena cava** rises at the **convexity** of the liver, - It splits into: - An **ascending portion** (*qism ṣā**ʿ**id*), - And a **descending portion** (*qism hābi**ṭ*), which was already described.   1. #### **The Ascending Portion and Its Branches** As it ascends: - It **pierces the diaphragm** (*al-**ḥ**ijāb*), - And releases **two branches** into it, - Which **nourish the diaphragm**. Then it passes **near the heart's outer membrane** (*ghilāf al-qalb*), - From here, it sends a **large branch** to the heart itself. #### **This Large Branch:** - Penetrates the **right atrium** (*udhn al-qalb al-ayman*), - Is considered the **greatest vein of the heart**, - More substantial than other veins and arteries. Ibn Sīnā explains why: - Other vessels serve **respiration** (carrying air), - But this one serves **nutrition**, - And nourishment is **heavier** and **more substantial** than breath, - So it needs a **wider vessel** and a **more robust wall**.   1. #### **Cardiac Membranes** As this vein enters the heart: - It is wrapped in **three membranes** (*agshiya thalātha*), - These are layered **inside-out** and **outside-in**, - To allow the heart to **draw in blood** during contraction, - And **prevent its return** during relaxation. Ibn Sīnā remarks: “These membranes are the **toughest** of all membranes.” ##### **Pulmonary Venous Artery (al-****ʿ****irq al-war****ī****d****ī****)** After the **vena cava** (al-ajwaf) sends its main **ascending branch** toward the **heart**, it continues toward the **lungs**: - It emits **three veins** toward the **lungs** (*al-ri**ʾ**a*), - These veins are situated **where the arteries bend** near the **left side**, - They enter the lungs via the **right chamber** of the heart.   ##### **Structure and Function** These pulmonary veins have a **dual structure**: 1. They are technically **veins**, because: - They **carry blood**, not breath, 2. But are **called “venous arteries”**, because: - They are **thick-walled** like arteries, - And functionally **deliver blood** from the heart to the lungs for **refinement**. Ibn Sīnā says: “This vessel has **two sheaths**, just like an artery.” Thus, the name **“venous artery”** is not a contradiction, but a reflection of its **dual nature** in **structure and purpose**.   ##### **Purpose of the Venous Artery** - Its main job is to **deliver very thin, light blood** (*dam rāqīq ghāyah al-raqqah*) - This blood is **fresh from the heart**, - Not yet matured or tempered like that flowing into the systemic arteries. - The **lungs** are very **delicate and fine in texture**, - So they must receive only the **most refined blood**, - To be **nourished properly** without being overwhelmed.   #### **Physiological Context** This **preliminary blood**: - Is still **close to the heart**, - Not yet "ripened" (*lam yanduj*) like the blood sent to the rest of the body, - Therefore, it requires a **direct pulmonary circuit**: - To be **filtered**, **oxygenated**, or **perfected** before systemic use. Ibn Sīnā, ahead of his time, appreciates that: - The blood delivered to the lungs by the **venous artery** is **not yet fully usable**, - But needs further **refinement** or **preparation** before being distributed. #### **The Arterial Vein (al-sharīān al-warīdī)** This vessel performs the **return function** in the **pulmonary circuit**: - It **emerges from the lungs**, - **Returns the refined blood** to the **left side of the heart**, - Specifically, it enters the **left atrium** (*udhn al-qalb al-aysar*).   #### **Why It’s Called a “Vein” and an “Artery”** Ibn Sīnā names it **“arterial vein”** because it has the **form of a vein** but the **function of an artery**: - Structurally: it is **thin-walled**, like veins, - Functionally: it **delivers blood into the heart**, not away from it, - Which is unlike typical veins that return blood to the **right side** of the heart. This naming reflects the vessel's **anomalous role**: - It behaves **arterially** (by carrying **oxygenated**, or "refined" blood), - But **enters the heart** like a vein. Ibn Sīnā’s naming system captures these subtleties long before modern physiology formalized the **pulmonary circulation**.   #### **Its Role in the Pulmonary Circuit** In Ibn Sīnā’s account: - The **venous artery** brings **raw blood** to the **lungs**, - The **lungs** act as a **refining organ**, - The **arterial vein** then returns **purified blood** to the **left atrium**, - From there, blood can be pumped to the rest of the body via the **aorta** (*al-**ʿ**irq al-a**ʿ**ẓ**am*). This reflects an **early functional understanding** of: - The **two-part circulation**, and - The **essential role of the lungs** in **blood refinement**, even without knowledge of oxygen. **The Descending Vena Cava (al-ajwaf al-hābi****ṭ****)** Once the **vena cava** completes its course **upward** through the **heart** and **lungs**, it also sends a **downward branch**, which travels: - In a **straight path** down the **back**, - Until it reaches the **fifth lumbar vertebra** (*al-faqrah al-khāmisah*), - Positioned **behind the heart**. At this junction: - A **ligamentous cushion** (*al-tawtha*) acts as a **support**, - Protecting it from being crushed by the **vertebral column** or **esophagus**. Then: - The vena cava **veers to the right**, - **Without crossing over**, it attaches to the **mesenteric membranes** (*al-aghshiyah*) - When it reaches the **diaphragm**, it pierces it to pass downward freely.   #### **Trajectory and Branching of the Descending Vena Cava** As it descends: - It follows the **vertebral column** until it reaches the **sacrum** (*ʿ**a**ẓ**m al-**ʿ**ajz*), - Along its route, it gives off numerous **branches** to organs and limbs:   1. ##### **Thoracic Branches** - One small, delicate **branch enters the lung vessels** (*wa**ʿ**ā**ʾ**al-ri**ʾ**a*), - Other branches go to: - The **trachea** (*qaṣabat al-ri**ʾ**a*), - **Each vertebra** it passes, - The **intercostal spaces**, - And the **spinal cord** (*al-nukhā**ʿ*).   1. ##### **Diaphragm and Upper Abdomen** After leaving the chest cavity: - Two arteries branch out to the **diaphragm** (*al-**ḥ**ijāb*), - Spreading right and left. Then: - Another branch feeds the **stomach**, **liver**, and **spleen**, - A thin offshoot also reaches the **bladder** (*al-mithānah*).   1. ##### **Intestinal and Renal Branches** Further along: - A branch supplies the **mesentery surrounding the small intestines** (*al-am**ʿ**ā**ʾ**al-diq**ā**q*) and **colon** (*qūlūn*). Next, **three arteries** branch off: - The **smallest** goes to the **left kidney** (*al-kulyah al-yusrā*), - Spreading into its **lobes** and surrounding tissues to sustain it. - The **other two** travel to both kidneys to help **draw water** from the blood, - Especially to remove **impure blood** drawn from the stomach and intestines.   1. ##### **Reproductive and Pelvic Branches** Two branches then extend to the **testicles or ovaries** (*al-unthayyayn*): - The **left testicular/ovarian artery** often joins a piece of the **left renal artery**, - It may even **originate entirely** from it. - The **right testicular/ovarian artery** consistently comes from the **main vena cava**, - But may rarely share fibers with the **right renal artery**. Another set of branches: - Spreads around the **rectum** (*al-ma**ʿ**ī**al-mustaq**ī**m*), - Sends fibers into the **spinal cord** via the **vertebral foramina**, - And spreads into both **flanks** and **genitals**.   #### **Division into the Iliac Arteries** When the **descending vena cava** reaches the **end of the spine**: - It **divides**, along with the **accompanying vein**, - Into **two main branches** forming the **Greek letter lambda (Λ)**, - One branch to the **right** (*yatīyāmin*), - One to the **left** (*yatīyāsar*). Each branch: - Travels over the **sacral bone** (*ʿ**a**ẓ**m al-**ʿ**ajz*), - And **descends toward the thigh** (*al-fakhdh*).   **Branches Before Entering the Thigh** Before reaching the thigh, each of these two main arteries gives off: 1. A **branch to the bladder** (*al-mithānah*), 2. A **branch to the navel** (*al-surrāh*), - These two branches **meet at the navel** in the fetus, - Becoming highly **visible in embryonic development**. In adults: - These embryonic vessels have **dried at their ends**, - Leaving their **bases intact**, which now give off small branches to: - The **muscles overlying the sacrum** (*ʿ**a**ẓ**m al-**ʿ**ajz*), - And in women, a **branch to the uterus** (*al-ra**ḥ**im*) — a small paired artery.   **Descent into the Legs** As the **iliac arteries** enter the **legs**, each gives rise to two major branches: 1. A **lateral (wa****ḥ****shī)** branch, 2. And a **medial (insī)** branch. Note: Even the **lateral branch** tends to **lean inward** (toward the body’s center). These branches: - Feed the **muscles** of the upper leg, - Then descend further, giving off: - A **large anterior branch** between the **big toe (ibham)** and **index toe (sabbābah)**, - And another **deep-penetrating branch** that traverses the **larger part of the leg**, - Running beneath the **venous network**.   **Physiological Commentary** Ibn Sīnā notes a **deep principle of design**: In many cases, **arteries accompany veins**, - Such as from the **liver to the navel** in fetuses, - Or in: - The **fifth lumbar vertebra**, - The **axilla**, - The **carotids**, - The **lungs**, - The **diaphragm**, - The **shoulder**, - The **digestive organs**, - And **lumbar/sacral plexuses**. He adds: - When arteries accompany veins in **deep organs**, the **artery rides atop the vein** (for dignity and hierarchy), - But in **surface anatomy**, the **artery dives beneath the vein**, - For **concealment** and **protection**, - With the **vein acting like a shield** (*junnah*).   **Reason for Arterial-Venous Pairing** Ibn Sīnā concludes with two reasons why **arteries accompany veins**: 1. So **veins can bind to the outer membranes** of arteries, - And **receive nutrients** from surrounding tissues via this connection. 2. So **each vessel can receive nourishment from the other** as needed. --- **Al-Jumla al-Khāmisa: The Veins** **Chapter One:** ### **On the Nature of Veins** Ibn Sīnā introduces the veins (*al-**ʿ**ur**ū**q al-s**ā**kinah*) by noting their: - **Origin**: All veins **originate in the liver** (*al-kabid*), - Their **primary purpose** is to **distribute nourishment** throughout the body. He distinguishes **two main veins** that first emerge from the liver:   1. #### **The Portal Vein (*al-bāb*)** - Emerges from the **concave side** (*al-jānib al-mu**ʿ**aqqar*) of the liver, - It **draws in nutrients** (*li-jadhb al-ghidhā**ʾ*) from the digestive tract **into** the liver. This vein is: - Essential for the **first step** of nourishment, - Bringing **raw digested material** to the liver for **processing and refinement**.   1. #### **The Hollow (Vena Cava) Vein (*al-ajwaf*)** - Emerges from the **convex side** (*al-jānib al-mun**ḥ**adib*) of the liver, - Its role is **distribution**: - It sends **processed nourishment** from the liver **outward** to the rest of the organs. So: - **al-bāb (the portal vein)** = **inward flow of raw nutrients**, - **al-ajwaf (the vena cava)** = **outward flow of refined nourishment**. This systemic logic reflects Ibn Sīnā’s principle that: The **liver is the factory of nutrition**, and the **veins are its delivery system**.   **Chapter Two:** ### **Anatomy of the Portal Vein (*al-bāb*)** Ibn Sīnā begins with the anatomical unfolding of the **portal vein**, which he defines as: “The vein whose function is to draw nourishment from the digestive organs into the liver.”   #### **Primary Structure and Division** - The **portal vein** first splits into **five main branches** within the **interior of the liver**: - These branches **fan out** toward the **convex surface** of the liver, - Much like **tree roots** drawing sustenance from below. One branch: - Extends to the **gallbladder** (*al-mirrārah*), - Serving its function in storing and concentrating bile.   #### **Branches Outside the Liver** From the portion of the portal vein facing the **concave side**, several **key branches** are described: 1. **Duodenal Branch** - A **small division** attaches directly to the **duodenum** (*al-ma**ʿ**ī**al-musamm**ā**ithnay**ʿ**ashar**ī*), - Drawing nourishment from early digesta. Sometimes: - **Minor offshoots** serve the **pancreas** (*al-jasad al-musammā banqrās*). 1. **Pyloric and Gastric Branches** - Another division extends to the **lower opening of the stomach** (*al-bawwāb*), - Drawing from the remaining food bolus. 1. **External Stomach Wall** - A third branch supplies the **outer (convex) side of the stomach**, - Because the **inner stomach wall** absorbs nutrients directly by contact with food, - But the **outer wall** requires vascular supply. 1. **Splenic and Pancreatic Network** - A fourth branch travels to the **spleen** (*al-**ṭ**i**ḥ**āl*), - And before reaching it, - Sends offshoots to the **pancreas** (*banqrās*), - Delivering the **clearest portion** of blood to prepare for splenic filtration. Once inside the spleen: - A **strong return branch** is sent back to the **left side of the stomach** for additional support. This same branch: - Splits again: - One part spreads over the **external left stomach wall**, - The other enters the **pyloric opening**, - To **stimulate it** and **draw out bitter black bile** (sawdāʾ), - This **prepares the digestive passage** and may **stimulate appetite**. --- Editing underway... **Further Down:** #### **Intestinal Supply** 1. **Colonic and Rectal Supply** - The fifth branch of the portal vein travels to the **colon** (*qūlūn*), - Absorbing from the **heavier remnants** of food. 1. **Small Intestine and Cecum** - The sixth branch travels toward: - The **ileum** (*ṣā**ʾ**im*), - The **jejunum and duodenum** (*al-lafā**ʾ**if al-daq**ī**qah al-muttaṣilah bi-l-a**ʿ**war*), - Absorbing nutrients from these finely divided food remnants.   **Chapter Three:** ### **The Vena Cava (*al-******ʿ******irq al-ajwaf*****) and Its Flow** #### **Origin and Internal Structure** - The **vena cava** originates **within the liver**, - Spreading into **hair-like filaments** throughout the liver’s interior, - Absorbing the **refined nutrients** processed there. Its **branches**: - Originate from the **convex surface** (*ḥ**adbat al-kabid*), - While those of the **portal vein** (*al-bāb*) arise from the **concave surface** (*ta**ʿ**q**ī**r al-kabid*), - Both networks **converge toward the interior** of the liver.   #### **Division into Ascending and Descending Tracts** After emerging from the liver, the **main trunk** of the vena cava splits into: **Ascending Tract (al-****ʿ****ā****riq al-ṣā****ʿ****id)** This branch: - **Pierces the diaphragm**, - Giving off **two branches** that nourish the diaphragm itself. - Then **aligns with the pericardium** (*ghilāf al-qalb*), - Sending a **large tributary** to nourish the **heart**, - Which **enters at the right atrium** (*udhn al-qalb al-ayman*). Ibn Sīnā calls this: **“The greatest of the heart’s veins”**, because: - Other veins bring **air (breezes)** for respiration, - But this one brings **dense nourishment** (blood), - Which requires **a larger passage** and **stronger walls**.   **Cardiac Sheaths and Functions** As this vein enters the heart, it is enveloped in **three sheaths**: - From **inside to outside** and vice versa. Their function is to: - Allow the **heart to draw nourishment during diastole**, - While **preventing backward flow** during systole. Ibn Sīnā describes these membranes as the **stiffest of the body**, to resist the high-pressure contraction of the heart.   **Branches to the Lungs** This vein sends **three branches** to the **lungs**, - Which arise near where the **aorta** emerges, - Looping toward the **left side**, - Then turning into the **right lung cavity**. Though it is a vein, Ibn Sīnā notes: - It has **two sheaths** like an artery, - And is therefore called a **“venous artery”** (*al-**ʿ**irq al-shar**īā**n**ī*). This reflects a profound understanding of: - The **pulmonary circulation**, - And the **dual nature** of pulmonary vessels in both **structure** and **function**. **The Descending Tract of the Vena Cava** After the vena cava branches upward to the heart and lungs, the **main trunk continues downward**, where it: - **Crosses the diaphragm**, - Moves toward the **abdomen and pelvis**, - And branches out extensively to **serve the internal organs** and **lower limbs**.   1. **Diaphragmatic Branches** Upon passing through the **diaphragm** (*al-**ḥ**ijāb*), - It gives off **two lateral branches**, - One to the **right**, one to the **left**, - Which nourish the **muscle and connective tissue** of the diaphragm.   1. **Gastric, Hepatic, and Splenic Tributaries** The vein gives off branches to: - The **stomach** (*al-mi**ʿ**da*), - The **liver** (*al-kabid*), - And the **spleen** (*al-**ṭ**i**ḥ**āl*), - Through fine **capillary offshoots**. These branches: - Work alongside the **portal system**, - Assisting in **nourishment and drainage** from the abdominal viscera.   1. **Renal Branches** Then come **branches to the kidneys** (*al-kulyatayn*): - Each kidney receives a **dedicated branch**, - Whose function is to: - **Draw excess water** from the blood, - Filtering it to form **urine**. Ibn Sīnā notes that the renal veins may also **collect impure blood**, especially that drawn from the **digestive system**, reinforcing the **filtration role** of the kidneys.   1. **Gonadal Veins** From here, **two small veins** descend to the **gonads**: - The **left gonadal vein** sometimes shares a root with the **left renal vein**, - The **right gonadal vein** arises directly from the **vena cava**. These supply and drain the: - **Testicles** in men (*al-khuṣiyatayn*), - **Ovaries and uterus** in women (*al-ra**ḥ**im*).   1. **Veins of the Bladder and Genitals** Some branches: - **Pass toward the bladder** (*al-mathānah*), - And others toward the **genitalia**, - Often **visible in fetuses** where they reach the **navel** (*al-surrat*). In adults, these vessels: - **Shrink and dry**, - Leaving only **residual origins**, - Which continue to serve the **muscles of the sacrum**.   1. **Iliac Veins and Lower Limbs** At the lower end of the spine: - The **vena cava bifurcates** into two **large branches**: - One to the **right thigh**, - One to the **left**. Each branch: - Gives off tributaries to the: - **Bladder**, - **Muscles of the pelvis**, - **Rectum**, and - **Urethra** (in men) or **uterus** (in women). Then it continues down: - Splitting into two **main leg veins**: - The **lateral (external)** branch, - And the **medial (internal)** branch. These eventually unite: - Just above the **ankle**, - Running alongside the **corresponding arteries**, - Delivering blood back toward the abdomen.   **Chapter Four:** ### **The Relationship Between Arteries and Veins** Ibn Sīnā observes that **arteries (****ḍ****awārib)** and **veins (****ʿ****ur****ū****q s****ā****kinah)** often accompany one another throughout the body. He outlines **two key principles** to explain this pairing:   1. **Positional Hierarchy of Vessels** - In **deep internal organs**, such as the **spine**, - The **artery rides atop the vein**, - Symbolizing a **hierarchy**: - The **vein carries denser substances** (blood), - While the **artery conveys the finer, nobler spirit** (*al-rū**ḥ*). Thus, in such cases, the **vein becomes a carrier** for the more valuable cargo. - In **superficial parts** of the body (e.g., limbs or skin): - The **artery is buried deeper**, - Hidden **beneath the vein**, - For **protection and concealment**, - Since it carries **vital life-force** (spirit), - And must be **sheltered** from harm. The **vein in these cases acts as a shield**, much like **armor protecting a noble treasure**.   1. **Functional Interdependence** Ibn Sīnā explains the necessity of arterial-venous coupling with **two reasons**: 1. **Shared Sheaths and Moisture Exchange** - The **veins are wrapped** in the same membranes (*aghshiya*) as the arteries. - This allows: - **Mutual nourishment**, - Moisture exchange between vessel walls, - And **shared temperature regulation**. 1. **Dynamic Exchange of Substances** - Each vessel draws something from the other: - The **vein may draw warmth or fine substances** from the artery, - The **artery may absorb vapor or remnants** from the surrounding veins.   **Conclusion of Chapter Four** This discussion provides a **conceptual anatomy**, not only of vessels, but of **systemic integration**: Veins and arteries are **paired**: - By **structure**, - By **function**, - And by a **natural philosophy** that views life’s flows as cooperative and hierarchic   **Chapter Five: The Veins – A General Classification** Ibn Sīnā identifies and classifies **five major types of veins**, which form the core of what he calls **al-****ʿ****ur****ū****q al-s****ā****kinah** — the “still” or “calm” vessels, in contrast with the **pulsing arteries** (*al-**ḍ**awārib*). These veins are defined according to: - Their **origin** (e.g., liver or heart), - Their **function** (e.g., carrying nourishment, draining waste), - And their **direction of flow** (ascending or descending).   **The Five Veins** 1. **The Portal Vein** (*al-bāb*): - Originates from the **concave side of the liver**. - Draws in digested material from the **intestines and stomach**, - And **delivers it to the liver** for processing. 2. **The Vena Cava** (*al-ajwaf*): - Emerges from the **convex surface of the liver**. - Distributes **refined nourishment** to the organs. - Splits into **ascending** (to heart and lungs) and **descending** (to abdomen and limbs) branches. 3. **The Hepatic Vein** (*al-**ʿ**irq al-kabid**ī*): - A branch within the liver that connects the **portal system** with the **vena cava**. - Acts as a **bridge** between the digestive intake and systemic output. 4. **The Pulmonary Vein** (*al-**ʿ**irq al-ri**ʾ**aw**ī*): - Despite being called a vein, it has **arterial characteristics**. - Carries **refined blood** from the **heart to the lungs**, - And assists in **air–blood mixture** essential for spirit production. 5. **The Umbilical Vein** (*al-**ʿ**irq al-surr**ī*): - Prominent in **fetuses**, connecting the **placenta to the liver**. - Delivers **nutrient-rich blood** from the mother, - And disappears or recedes after birth, leaving **traces or ligaments**.   **Final Notes** Ibn Sīnā concludes this section by emphasizing: - The **integration of all veins** into the **greater system of nourishment**, spirit generation, and waste removal. - The **wisdom of design** — that each vein, though distinct in **route**, **origin**, or **function**, is coordinated with all others in a **single biological network**.       ### *Related*