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

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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.

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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 (taʿālīm).

 

Teaching One:

Comprising Two Chapters

Chapter One:

I say: Medicine (ṭibb) 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’ (ʿilm) or ‘theory’ (naẓar), and the second is called ‘practice’ (ʿamal).

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 (raʾy) 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 (manṭiq), 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 (ʿawāriḍ) that occur in states of health and disease.

It has been established in the real sciences (ʿulūm ḥaqīqiyyah) 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 (rūḥ), and the more remote are the humors (akhlāṭ), and more remote still are the elemental components (arkān).
2. Efficient causes (asbāb fāʿiliyyah): 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 (arwāḥ) 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 (ʿilāj bi’l-dawāʾ), and manual therapy (ʿilāj 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 (akhlāṭ),
• The simple and composite organs,
• The spirits (arwāḥ),
• The natural, vital, and psychic faculties,
• The actions (afʿāl),
• 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 (ʿilm al-ṭabīʿiyyāt), until they ultimately ascend to first philosophy (al-ḥikmah 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 (ijmāʿ), 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 (hawāʾ)

The heavy elements are:

• Water (māʾ)
• Earth (arḍ)

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 (ruṭūbah) 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-muḥarrik al-awwal) is the soul (nafs), by the permission of its Creator.

These, then, are the Elements.

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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 muḍāddah)—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 (ḥarārah)
• Coldness (burūdah)
• Moisture (ruṭūbah)
• Dryness (yubūsah)

It has been established that all physical bodies (ajsām kāʾinah fāsidah)—those subject to generation and corruption—derive their temperaments from these qualities, in accordance with what rational division (al-qismah al-ʿaqliyyah) necessitates.

There are two main logical possibilities:

1. Moderate Temperament (mizāj muʿtadil):
   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 māʾil):
   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-muʿtadil) 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 muʿtadil 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 muʿtadil muʿtabar—the “considered moderation” as it pertains to human bodies.

Thus, the standard of iʿtidāl (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 (nawʿ) 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.

 

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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 (Muʿtadil) – balanced in all four qualities.
2. Hot only (ḥārr faqaṭ)
3. Cold only (bārid faqaṭ)
4. Moist only (raṭb faqaṭ)
5. Dry only (yābis faqaṭ)
6. Hot and moist (ḥārr raṭb)
7. Hot and dry (ḥārr yābis)
8. Cold and moist (bārid raṭb)
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 (akhlāṭ),
• 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-Akhlāṭ) #

Chapter One:

On the Nature of the Humors #

I say:
The humors (akhlāṭ) 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 (ṣafrāʾ) — Hot and dry
3. Black bile (sawdāʾ) — 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-maʿidī) — 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 (quwāʾ) 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-ṭabīʿiyyah)
2. Vital Faculty (al-quwwah al-ḥayawāniyyah)
3. Psychic Faculty (al-quwwah al-nafsāniyyah)

Each of these corresponds to a particular spirit (rūḥ) 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 (ghidhāʾ),
• 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-rūḥ al-ṭabīʿī), 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-rūḥ al-ḥayawānī),
• 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 (ḥiss),
• Voluntary motion (ḥarakah 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-rūḥ 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-Afʿāl) of the Body #

Chapter One:

On the Definition of Action and Its Relation to Faculty #

I say:
An action (fiʿl or ʿamal) 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 (ʿillah) of the action,
• The spirit is the medium or vehicle (wāsiṭah),
• 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 (afʿāl ṭabīʿiyyah):
   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 (afʿāl ḥayawāniyyah):
   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 (afʿāl nafsāniyyah):
   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 (ʿilm al-afʿāl) completes the physician’s understanding of the body as a living, dynamic system, composed of matter (māddah), form (ṣūrah), faculties (quwā), spirits (arwāḥ), and purposeful actions (afʿāl).

 

This concludes Teaching Six and completes Discipline One of Book One: the foundational theoretical framework of the science of medicine.

 

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Discipline Two

On the General Principles Governing the Powers of Simple Medicaments (fī kulliyyāt aḥkām quwā al-adwiyah al-mufradah) #

Chapter One:

On the Definition of Medicament and Its Active Power #

I say:
A simple medicament (dawāʾ mufrad) is any substance whose composition consists of a single essential nature (ṭabīʿah wāḥidah), 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 fāʿilah).

The power (quwwah) of the medicament is what brings about this change. This power can be:

• Heating (muḥarrir),
• 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 (ḥiss):
   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 arbaʿah):

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 (qābiḍ): contracts tissue and halts discharges.
• Laxative (mushil): promotes evacuation of excess humors.
• Resolvent (muhallil): dissolves swellings and hardenings.
• Attenuant (mulaṭṭif): thins thick substances.
• Incisive (qāṭiʿ): 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-amrāḍ al-juzʾiyyah al-wāqiʿah bi-ʿuḍw ʿuḍw min al-insān min al-farq ilā al-qadam ẓāhirihā wa-bāṭinihā)

 

Introduction to Discipline Three

In this section, I begin addressing the specific diseases (amrāḍ juzʾiyyah) 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 (tashrīḥ) of the organ: its form and structure.
2. Function (manfaʿah): the role the organ plays in the body.
3. Preservation (ḥifẓ al-ṣiḥḥah): how to maintain its health.
4. Diseases (amrāḍ) that afflict it, in general terms.
5. Causes (asbāb) of those diseases.
6. Signs (ʿalāmāt) indicating disease or imbalance.
7. General therapeutic principles (qawāʿid ʿilājiyyah kulliyyah) relevant to treatment.
8. Particular treatments (ʿilāj juzʾī): using appropriate simple or compound remedies.

If the anatomy or function of an organ has already been discussed earlier—especially among the simple organs (aʿḍāʾ 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 (aʿḍāʾ),
• 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 (iʿādat al-iʿtidāl) 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-raʾs wa-mā yaḥtawī ʿalayh)

 

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 (ṭabaq al-jumjuma), and is enclosed by membranes (al-ṣafāʾif) 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-ʿaṣab) which spread throughout the body, controlling movement, sensation, and mental operations such as thought, memory, imagination, and judgment.

2. 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.

3. 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 (sawdāʾ),
• 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, ḥuzn), or confusion (khubṭ).

4. 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 (ḥijāmah), or nasal administration (saʿūṭ, naṭūr).
• 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.

5. Example: Headache (Ṣudāʿ) #

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 (riyāḥ) → 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-ʿaynayn)

1. Anatomy and Function of the Eye #

The eye (ʿayn) 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 (rūḥ al-māʾ), lying just beneath.
• The lens (ʿadasah), the central body responsible for focusing.
• The vitreous humor (rūḥ al-zujāj), the gel-like substance filling the main cavity of the eye.
• The optic nerve (ʿaṣab 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.

2. 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 (kuḥl) 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.

3. General Eye Disorders #

Eye diseases include:

• Inflammation (ramad): redness, swelling, burning, often due to heat or vapors.
• Weakness of vision (ḍuʿf al-baṣar): caused by overuse, old age, or dryness.
• Night blindness (ʿamā al-layl): typically due to excess cold or liver dysfunction.
• Flow of tears (sīlān al-dumūʿ): may result from irritation, obstruction, or excessive moisture.
• Opacity (kudrah) or cataract (al-māʾ al-nāzil): accumulation of thick humor in the lens or pupil.
• Itching, dryness, or heaviness: symptoms of imbalance in temperament or humor.

4. 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 (kuḥl),
• 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-ẓāhirah), including the auricle (ṣinw) and the auditory canal.
2. The middle ear (al-wusṭā), which contains the tympanic membrane (ghishāʾ al-ṭabl) and a cavity filled with air.
3. The inner ear (al-bāṭinah), where the auditory nerve (ʿaṣab al-samʿ) 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.

2. 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.

3. General Ear Disorders #

Common diseases of the ear include:

• Pain (wajaʿ 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 (riyāḥ) or vapor trapped in the canals.
• Itching or tingling: often caused by irritants, dryness, or insects.

4. 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 (ʿaṣab 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.

 

2. 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.

3. 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 ḍuʿfuhu): from cold temperament, head congestion, or nerve weakness.
• Irritation and itching: due to dryness or allergic reactions.
• Epistaxis (ruʿāf – nosebleeds): from heat, dryness, or rupture of fine vessels.
• Ulcers and sores (qurūḥ): often caused by acrid vapors or infection.
• Polyp growths (ḥamiḍ): soft or hard, arising from thick humors.

 

4. 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 (naṭūr).
• 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 (ḥanak),
• 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.

 

2. 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.

 

3. 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 (wajaʿ), decay (tasawwus), or looseness.

 

4. 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-ḥalq wa-l-lūz wa-mā yataʿallaq bihimā)

 

1. Anatomy and Function of the Throat and Tonsils #

The throat (ḥalq) 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-ḥalq),
• The larynx (ḥanjarah), which produces voice,
• The epiglottis (laḥmīyah), 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.

 

2. 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.

 

3. 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 (ḥasakat fī al-ḥalq): sometimes imaginary, sometimes due to small ulcers or thick secretions.

 

4. 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 (ḥijāmah) 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-riʾah)

 

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 (riʾah) 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.

 

2. 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.

 

3. 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 (suʿāl): may be dry or productive, due to irritation, phlegm, or heat.
• Shortness of breath (ḍīq 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.

 

4. 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-amrāḍihi)

 

1. Anatomy and Function of the Heart #

The heart (qalb) is the chief vital organ (ʿuḍw al-raʾīsī al-ḥayawānī), 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-rūḥ al-ḥayawānī).

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.

 

2. 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.

 

3. Diseases of the Heart #

Heart diseases may be:

• Structural (ṣinfī) — such as congenital defects or trauma;
• Functional (fiʿlī) — 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 (ighmāʾ): collapse of consciousness due to weakness in the heart’s heat or spirit.
• Cardiac pain (wajaʿ al-qalb): sharp or constricting pain, often from accumulated bile or cold vapor.
• Heart weakness (ḍuʿf al-qalb): general fatigue, loss of stamina, or coldness in the chest.
• Excessive heat: may produce thirst, restlessness, dry mouth, and insomnia.
• Emotional afflictions (marāḍ nafsānī): melancholy, fear, or passion that disturb the heart’s balance.

 

4. 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-amrāḍihā)

 

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-ṭabīʿiyyah). 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 (akhlāṭ).

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.

 

2. 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.

 

3. Diseases of the Liver #

Liver diseases may arise from:

• Humoral imbalance, particularly excess yellow bile (ṣafrāʾ) or black bile (sawdāʾ),
• 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) (istisqāʾ): fluid retention due to liver failure.
• Loss of appetite, digestive heaviness, and melancholy: often traced to hepatic dysfunction.

 

4. 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-miʿda wa-amrāḍihā)

 

1. Anatomy and Function of the Stomach #

The stomach (miʿda) 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.

2. 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.

 

3. 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 (sūʾ al-hadhm): heaviness, bloating, belching, or nausea.
• Weak digestion: due to cold, dryness, or phlegm.
• Gastric inflammation (waram al-miʿda): 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 (riyāḥ): due to weak digestion and vapor accumulation.
• Nausea and vomiting (ghathayān wa-qayʾ): may arise from excess matter, obstruction, or nervous stimulation.
• Hiccups (shaḥīq): result of diaphragmatic disturbance or gastric irritation.

 

4. 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-amʿāʾ wa-l-muʿidah wa-amrāḍihā)

 

1. Anatomy and Function of the Intestines #

The intestines (al-amʿāʾ) are the tubular structures that extend from the pylorus of the stomach to the anus. They are divided into:

1. Small intestines (al-amʿāʾ al-ṣighār): where further digestion and absorption of nutrients occurs.
2. Large intestines (al-amʿāʾ al-kibār): 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.

 

2. 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.

 

3. Common Intestinal Disorders #

Disorders may involve:

• Motion: constipation (qabḍ), 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 (zḥīr): inflammation with bloody or mucous stools—often due to corrupted bile or ulceration.
• Prolapse of rectum (squūṭ al-muʿidah): due to strain, weakness, or dryness.

 

4. 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 (ḥuqan) 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.

 

2. 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.

 

3. Common Diseases of the Kidneys and Bladder #

Typical disorders include:

• Back pain (wajaʿ al-kulā): may result from inflammation, strain, or accumulation of waste.
• Difficulty in urination (ʿusrat 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 (ḥabs al-bawl): from blockage, nervous dysfunction, or thickened humors.
• Stone formation (ḥaṣāʾ): 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.

 

4. 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 (ḥuqan) 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-ʿaḍw al-nāsil wa-l-raḥim wa-amrāḍihimā)

 

1. Anatomy and Function of the Reproductive Organs #

For Men: #

The male reproductive organ (al-ʿaḍw 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 (raḥim),
• 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 (ḥayḍ) to cleanse excess blood.

 

2. 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.

 

3. Common Disorders #

In Men: #

• Impotence (ʿajz): from cold temperament, exhaustion, or obstruction in semen channels.
• Premature ejaculation (suraʿat al-inzāl): often from weakness of restraint or heat.
• Seminal emission during sleep (iḥtilām): 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 (ḥabs al-ḥayḍ): due to cold, fear, or blockage.
• Excessive menstruation (kathrat al-ḥayḍ): from heat or blood surplus.
• Womb pain (wajaʿ al-raḥim): from swelling, dryness, or cold vapor.
• Uterine prolapse (squūṭ al-raḥim): often from childbirth trauma or weakness.
• Sterility (ʿuqm): due to dryness, obstruction, poor semen retention, or systemic weakness.

 

4. 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-aʿḍāʾ al-ḥarakiyyah)

 

1. Anatomy and Function #

The musculoskeletal system consists of:

• Bones (ʿiẓām): rigid structures providing support and framework.
• Joints (mafāṣil): connections between bones allowing motion and flexibility.
• Muscles (ʿaḍalāt): soft tissues enabling movement by contraction and relaxation.
• Tendons (ʿuṣb or rawābiṭ): cords connecting muscles to bones.
• Ligaments (arbaṭah): connective tissues stabilizing joints.
• Cartilage (ghuḍrūf): 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.

 

2. 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.

 

3. Common Ailments #

• Joint pain (wajaʿ al-mafāṣil): from cold, dryness, or swelling of humors.
• Stiffness (taṣallub): often due to cold and dryness, especially in the elderly.
• Dislocation (khalʿ): 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 (dhuʿf al-ʿaḍalāt): 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 (ʿirq al-nasāʾ): pain along the hip and leg, caused by cold humors or obstruction along the nerve tract.

 

4. Therapeutic Principles #

• For pain and stiffness: warming oils (e.g., mustard, cinnamon, clove) and fomentations; dry cupping (ḥijāmah) where appropriate.
• For dislocations and fractures: reduction (manual adjustment), splinting (taṣfīḥ), 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-shaʿr wa-l-zīnah)

 

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).

 

2. Hair and Its Qualities #

Hair (shaʿr) 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.

 

3. Preservation and Beautification of the Skin and Hair

For the Skin: #

• Bathe with lukewarm water and cleansing agents (e.g., sīd, ḥimṣ 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.

 

4. 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-amrāḍ allatī idhā waqaʿat lam takhtaṣṣ bi-ʿuḍwin bi-ʿaynihi)

 

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-Ḥummayāt) #

A fever (ḥummá) is the result of heat generated inside the body due to blocked humors, putrefaction, or external invasion. It may be:

• Ephemeral (ḥummá nāshiʾah): caused by transient environmental or dietary factors.
• Humoral (ḥummá 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 (hindibāʾ), coriander.
• Light diet: gruels, barley soup, avoiding meat, fats, and wine.
• Sleep and rest: critical to restore vital energy.

 

2. 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 ḥamqāʾ), activated charcoal.
• Emergency methods: cupping near site, cold compresses, emetics.

 

3. Wasting Conditions and Emaciation (Al-Dhubl wa-l-Nuḥūl) #

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.

 

4. 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.

 

5. Fatigue and Weakness (Al-Taʿab wa-l-Daʿf) #

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.

 

6. Sleep Disorders (Al-Nawm wa-l-Sahar) #

• Insomnia (sahar): from excess heat, worry, or dryness.
• Excess sleep (nawm zāʾid): 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.

 

2. 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.

 

3. Categories of Compound Remedies #

4. According to Form:

• Electuaries (maʿājīn): 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 (ḥubūb): compacted forms for ease of use.
• Ointments (marhamāt): for external application.
• Enemas (ḥuqan) and suppositories: for cleansing and direct absorption.

1. According to Effect: #

• Laxatives (mushilāt),
• Diuretics (mubawwilāt),
• Tonics (muqawwiyāt),
• Digestives (hāḍimāt),
• Emetics (muqayyīʾāt),
• Refrigerants (mubarridāt),
• Warmers (muḥarrikāt).

Each is chosen based on the humoral imbalance, the organ affected, and the seasonal or regional climate.

 

4. 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.

 

5. 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-amrāḍ al-juzʾiyyah al-waqiʿah bi-ʿuḍwin ʿuḍw),
4. General Diseases and Adornment (al-amrāḍ allatī lam takhtaṣṣ bi-ʿuḍw 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.

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On the Categories and Degrees of Temperamental Moderation (al-Iʿtidāl) #

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 (arwāḥ) 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 (laḥm), 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 ʿAmr.

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 (iʿtidāl), we may proceed to the study of non-moderate or deviant temperaments (amzija ghayr muʿtadila). 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 muʿtadila)

 

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 (muḍāddayn), 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.

2. 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 (ḥār 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.

 

2. Hot and Moist (ḥār raṭb) #

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.

 

3. Cold and Moist (bārid raṭb) #

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.

 

4. 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.

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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 (ṣafrāʾ karrāthiyyah).

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 (rūḥ) 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 (shaḥm),
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 (shaḥm),
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.

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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-Namāʾ) — also called childhood (ḥadātha), 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 (muktaḥilīn), 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 (ṭufūlah): 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 (tararraʿ): 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 (ruʿāf),
  • Their temperament inclines toward yellow bile (ṣafrāʾ), 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 (ʿalāmāt) of temperaments—both general and specific.

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Chapter Four:

On the Humors (al-Akhlāṭ) #

Section One:

The Nature of Humor and Its Types #

Definition of Humor (al-Khalṭ): #

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 (ṣafrāʾ)
4. Black bile (sawdāʾ)

On Blood (al-Dam) #

Blood is warm (ḥār) and moist (raṭb) 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 ṣafrāʾ), another may become thick black bile (murrat sawdāʾ), 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 (ʿakir)
• 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 (Manfaʿa): #

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-ṭabīʿī) #

Unnatural phlegm includes excessive and qualitatively deviant types. These may differ:

• In consistency, even perceptibly to the senses, such as:
  • Mucous (mukhāṭī) 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 (ḥāmiḍ): 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 (ʿafṣ) 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 (Ṣafrāʾ) #

Yellow bile is of two types:

• Natural (ṭabīʿī)
• Excess and unnatural (faḍl ghayr ṭabīʿī)

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-ṣafrāʾ)
• Milky bile (al-mirrah al-muḥīyah)

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 (ṣafrāʾ muḥtaraqa), 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 (Sawdāʾ) #

Black bile is also of two types:

• Natural (ṭabīʿī)
• Excess / unnatural (faḍl ghayr ṭabīʿī)

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 (Faḍliyya Ghayr Ṭabīʿiyya) #

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-sawdāʾ al-iḥtirāqiyya).

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.

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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-mamḍūgh) 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-ʿirq al-ṭāliʿ) 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-muʿtadil al-haqīqī):
   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-muʿtadil 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-māʾil):
   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 (ḥār 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.

2. 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.

3. Moist Temperament (rāṭib 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.

4. 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.

5. 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.

6. Balanced Temperament (al-mizāj al-muʿtadil): #

• 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 (sawdāʾ), 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.

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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.

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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 (ʿiqāb). 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.

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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.

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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.

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Chapter Two:

Anatomy of the Skull (al-Qaḥf) #

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.

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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 (ḥarqufa or ʿaẓm al-khāṣira).
2. The part that faces forward
   • Is called the pubic bone (ʿaẓm al-ʿāna).
3. The part toward the back
   • Is called the ischium or hip bone (ʿaẓm al-wark).
4. The lowest and innermost part
   • Is called the acetabulum (ḥaqq 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-raḍfa),

• 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 (kaʿb) —
   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 (kaʿb) 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-ʿajz) 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-ḥurqafa), also known as the hip bone (ʿaẓm al-khāṣira).
2. The part that faces forward is called the pubic bone (ʿaẓm al-ʿāna).
3. The part facing backward is called the ischium (ʿaẓm al-warak).
4. The part facing downward and medially is called the acetabulum (ḥaqq 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-raḥim),
• The semen-conveying vessels in males,
• The anus (al-maqʿada),
• 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 (ḥaqq 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-raḍfa) —

• 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-kaʿb) –
   • Completes the joint with the shin (sāq).
2. The Heel Bone (al-ʿaqib) –
   • The main pillar of foot stability.
3. The Navicular Bone (al-zawraqī) –
   • Forms the foot arch.
4. Four tarsal bones (ʿiẓām 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 (ʿiẓām al-masḥṭ) –
   • 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 (ʿajz), 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-ḥurqafa) or hip bone.
2. The part that lies anteriorly is called the pubis (ʿaẓm al-ʿāna).
3. The part that lies posteriorly is called the ischium (ʿaẓm al-wirk).
4. The part that lies inferiorly and medially is called the acetabulum (ḥaqq 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-muqʿada),
• 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 (ḥaqq 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-raḍfa), 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 (kaʿb) —
   • Forms the main ankle joint with the shin.
2. The calcaneus (ʿaqib) —
   • 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-kaʿb) 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-waḥshī).

The ankle connects to the navicular bone (al-ʿaẓm al-zawraqī) in the front.

• This navicular bone, in turn:
  • Connects posteriorly to the heel (al-ʿaqib),
  • Anteriorly to three of the tarsal bones,
  • And laterally to the cuboid bone (al-ʿaẓm 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 (ʿiẓām 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 (ʿuqab) and ligaments (rubāṭ).

• 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 (ghishāʾ),
• 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 (ʿaḍala).

• 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-iṭbāq) raises it.
• Chewing (al-saḥq) shifts it side to side.

Muscles for Closing the Jaw #

• These include two muscles, known as the temporal muscles (ʿaḍlatā 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 (ʿaẓm 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-raʾs) #

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-ḥanjara) is a cartilaginous organ created as an instrument for sound production. It consists of three main cartilages:

1. Thyroid cartilage (al-ghuḍrūf 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 (dirʿ) or part of a buckler (turs).

 

1. Cricoid cartilage (al-ghuḍrūf 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-shaʿb al-hawāʾīyah).
   • It provides support and stability for the entire structure.
2. Epiglottis (al-ghuḍrūf 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.

2. 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.

2. 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.

3. 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.

2. 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-ʿaẓm 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 (ḥulqūm) 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.

2. 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.

2. 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.

2. 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.

2. 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.

3. 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.

4. 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.

5. 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.

2. 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.

2. 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).

2. 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 rūḥ ḥayawānī (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).

 

2. 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.

 

3. Origins and Circulatory Pathways #

• Arteries:
  • Originate from the left ventricle of the heart (al-jayb al-aysar).
  • Main trunk: al-sharāyīn al-awraṭī (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.

 

4. 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-ḥarārah 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-ʿawraṭī al-ṣāʿid) #

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-ghāʾir) 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-ibṭ), 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-ʿaẓm al-ḥijrī) 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 (nضuj). 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-ʿurūq al-warīdiyya al-nāzila) 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 rūḥ, 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 rūḥ 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-ḥijāb).

From here, it descends further, continuing along the spine to reach the sacrum (ʿaẓm al-ʿajz).

 

Branches Along the Thorax and Abdomen #

As it descends, it gives rise to:

• A small branch to the lung (al-riʾa), which reaches the bronchi.
• One branch for each vertebra, reaching:
  • The intercostal spaces (bayn al-aḍlāʿ),
  • And the spinal cord (al-nukhāʿ).

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-miʿda),
  • Liver (al-kabid),
  • Spleen (al-ṭiḥāl).

From the liver, a branch continues to the bladder (al-mithāna).

Then, a branch reaches the intestinal mesentery surrounding:

• The jejunum (al-amʿāʾ al-diqāq),
• 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-ṣāḥib) 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 (ʿaẓm al-ʿajz), 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-qaḍīb) in men, and the uterus (al-raḥim) 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 (waḥshī),
• 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-ibṭ),
• The carotids (al-sabātiyyān) as they split and spread into the rete mirabile and placenta,
• Those that reach the diaphragm (al-ḥijāb),
• 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-ʿurūq) #

The stationary veins (al-ʿurūq al-sākina) 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-muʿtaṣir), 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-mutaḥaddib), 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-ʿirq al-musammā bil-bāb). 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-miʿā al-musammā ithnay ʿashar), 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-miʿda), especially near the pylorus (bawwāb al-miʿda), 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-ṭiḥāl), 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 (ḥudbat al-miʿda),
   • 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 (maʿī qūlūn), assisting in absorption.
8. The sixth is mostly distributed around the jejunum (al-ṣāʾim) and parts of the ileum (al-lifāʾif al-daqīqa) attached to the cecum (al-aʿwar), 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 (ḥadabat al-kabid),
• While the branches of the portal vein enter from its concave surface (taqaʿur 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 (ṣāʿid),
2. A descending branch (hābiṭ).

 

The Ascending Branch #

• Passes through the diaphragm (al-ḥijāb) 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 (māʾiyyat 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-raḥim),
• In males, the vein reaches the tip of the penis (aṭrāf al-qaḍīb),
• 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 (ʿaẓm al-ʿajz),
• 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 (waḥshī),
  • 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 (yamtaṭī 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 (ḍawārib) and veins (ʿurūq) 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-ibṭ),
  • 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 (ʿurūq ʿaẓm al-ʿajz).

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-ʿurūq) 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-ʿurūq al-sākina) 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-munḥanī) 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.

2. The Outer End (toward the digestive organs): #

This outer end splits into:

• A small branch connecting directly to the duodenum (al-miʿā al-musammā ithnay ʿashar),
  • It draws nutrients directly from there.
• A second branch spreads through the lower part of the stomach, particularly near the pyloric orifice (bawwāb al-miʿda).

 

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-ṭiḥāl), 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.

3. Third Branch

• Extends to the left side of the abdomen (al-jānib al-aysar),
• Divides into small veins around the rectum (al-maʿī al-mustaqīm),
• Its role is to absorb the remaining heaviness (al-thiql) of what is left from digested food.

4. Fourth Branch

• Divides like fine threads (ka-l-shaʿr),
• 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.

5. Fifth Branch

• Spreads through the networks of veins that surround the colon (qūlūn),
  • For final-stage nutrient absorption.

6. Sixth Branch

• Primarily nourishes the jejunum (al-ṣāʾim) and partially the ileum (al-lifāf al-daqīqa),
  • Which connect to the cecum (al-aʿwār),
• 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-shaʿr) that:

• Draw nourishment from the portal vein’s branches,
• Particularly from the rounded convex side (ḥadabat al-kabid) of the liver, flowing inward.

Meanwhile, the branches of the portal vein move from the concave side (taqaʿur 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-ḥijāb),
  • 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-ghidhāʾ),
  • 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 (ʿinda 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-ʿirq al-sharīānī)” —
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-hābiṭ) #

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-ʿurūq) around the small intestines (al-amʿāʾ al-diqāq) 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.

2. & 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-maʿī al-mustaqīm),
• Branches to the spinal cord (al-nukhāʿ),
  • 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-ʿirq al-ajwaf al-kabīr) 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 (ʿaẓm al-ʿajz),
• 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-qaḍīb),
  • And a branch to the uterus in women (al-raḥim),
    • 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 (waḥshiyy) 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” (ḍawārib) 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-ghidhāʾ) from the intestines and convey it to the liver.

 

Initial Branching of the Portal Vein Inside the Liver #

The deep end (ṭarafuhu al-ghāʾir) 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 (ṭarafuhu al-ẓāhir) of the portal vein divides into eight branches:

1. First Branch

• Connects directly to the duodenum (al-miʿā al-musammā ithnay ʿashar),
• Draws nourishment from it.
• It also sends tiny twigs into the pancreas (al-jirm al-musammā bānqrās).

2. Second Branch

• Reaches the lower part of the stomach (asāfil al-miʿda),
• Especially around the pylorus (al-bawwāb),
• Draws semi-digested food for liver processing.

3. 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.

4. Fourth Branch

• Extends to the spleen (al-ṭiḥāl),
• 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 (ḥadbat al-miʿda),
    • Some reach its left outer side,
    • Others burrow inward to deliver black bile (sawdāʾ) and stimulate appetite.

5. Fifth Branch

• This branch extends toward the left side (al-jānib al-aysar),
• It branches into the venous loops (judhūl al-ʿurūq) surrounding the rectum (al-maʿī al-mustaqīm),
• Its function is to absorb the denser remnants of nourishment from the lower digestive tract.

6. Sixth Branch

• It splits into two parts:
  • One spreads through the outer right side of the gastric curve (ḥadbat al-miʿda),
    • Facing the area served by the fourth branch on the left.
  • The second heads toward the right omentum (thirb) and disperses within it.

7. Seventh Branch

• This one distributes through the venous channels around the colon (maʿī qūlūn),
• Assists in drawing remaining nutrients from the partially digested material.

8. Eighth Branch

• Mostly branches around the jejunum (al-ṣāʾim),
• And the ileum (al-lafāʾif al-daqīqa) near the cecum (al-aʿwar),
• Draws what is still nutritive from this final stretch of the small intestine.

Ibn Sīnā concludes:
“Know this” (faʿlam dhālika), 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-taqʿīr),
• While the caval branches (al-ajwaf) enter from the convex side (al-ḥudba).

 

2. 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 ṣāʿid),
  • And a descending portion (qism hābiṭ), which was already described.

 

3. The Ascending Portion and Its Branches #

As it ascends:

• It pierces the diaphragm (al-ḥijāb),
• 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.

 

4. 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-ʿirq al-warīdī) #

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-riʾa),
• 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-ʿirq al-aʿẓam).

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-hābiṭ)

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 (ʿaẓm al-ʿajz),
• Along its route, it gives off numerous branches to organs and limbs:

 

1. Thoracic Branches #

• One small, delicate branch enters the lung vessels (waʿāʾ al-riʾa),
• Other branches go to:
  • The trachea (qaṣabat al-riʾa),
  • Each vertebra it passes,
  • The intercostal spaces,
  • And the spinal cord (al-nukhāʿ).

 

2. Diaphragm and Upper Abdomen #

After leaving the chest cavity:

• Two arteries branch out to the diaphragm (al-ḥijāb),
  • Spreading right and left.

Then:

• Another branch feeds the stomach, liver, and spleen,
• A thin offshoot also reaches the bladder (al-mithānah).

 

3. Intestinal and Renal Branches #

Further along:

• A branch supplies the mesentery surrounding the small intestines (al-amʿāʾ al-diqāq) 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.

 

4. 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-maʿī al-mustaqīm),
• 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 (ʿaẓm al-ʿajz),
• 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 (ʿaẓm al-ʿajz),
• And in women, a branch to the uterus (al-raḥim) — 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 (waḥshī) 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-ʿurūq al-sākinah) 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-muʿaqqar) of the liver,
• It draws in nutrients (li-jadhb al-ghidhāʾ) 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.

 

2. The Hollow (Vena Cava) Vein (al-ajwaf) #

• Emerges from the convex side (al-jānib al-munḥadib) 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-maʿī al-musammā ithnay ʿasharī),
  • Drawing nourishment from early digesta.

Sometimes:

• Minor offshoots serve the pancreas (al-jasad al-musammā banqrās).

2. Pyloric and Gastric Branches

• Another division extends to the lower opening of the stomach (al-bawwāb),
  • Drawing from the remaining food bolus.

3. 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.

4. Splenic and Pancreatic Network

• A fourth branch travels to the spleen (al-ṭiḥāl),
  • 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.

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Editing underway…

Further Down:

Intestinal Supply #

5. Colonic and Rectal Supply

• The fifth branch of the portal vein travels to the colon (qūlūn),
  • Absorbing from the heavier remnants of food.

6. Small Intestine and Cecum

• The sixth branch travels toward:
  • The ileum (ṣāʾim),
  • The jejunum and duodenum (al-lafāʾif al-daqīqah al-muttaṣilah bi-l-aʿwar),
  • Absorbing nutrients from these finely divided food remnants.

 

Chapter Three:

The Vena Cava (al-ʿirq 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 (ḥadbat al-kabid),
• While those of the portal vein (al-bāb) arise from the concave surface (taʿqīr 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-ʿāriq al-ṣāʿid)

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-ʿirq al-sharīānī).

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-ḥijāb),

• It gives off two lateral branches,
  • One to the right, one to the left,
• Which nourish the muscle and connective tissue of the diaphragm.

 

2. Gastric, Hepatic, and Splenic Tributaries

The vein gives off branches to:

• The stomach (al-miʿda),
• The liver (al-kabid),
• And the spleen (al-ṭiḥāl),
  • Through fine capillary offshoots.

These branches:

• Work alongside the portal system,
• Assisting in nourishment and drainage from the abdominal viscera.

 

3. 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.

 

4. 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-raḥim).

 

5. 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.

 

6. 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 (ḍawārib) and veins (ʿurūq sākinah) 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-rūḥ).

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.

 

2. 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-ʿurūq al-sākinah — the “still” or “calm” vessels, in contrast with the pulsing arteries (al-ḍawārib).

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-ʿirq al-kabidī):
   • 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-ʿirq al-riʾawī):
   • 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-ʿirq al-surrī):
   • 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.