Inderbir Singh's Textbook of Anatomy (Volume 1) Sudha Seshayyan
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1General Anatomy
2

Science of AnatomyChapter 1

Anatomy is the science that deals with the structure of the body. This name was given by Aristotle about 2300 years ago. Study of the structure of living beings was done by dissecting the body and seeing the various structures in position; hence, the term anatomy (ana+tome=cutting up) was given. The term applies to the study of the structure of all living beings; specificity is given by adding a prefix that indicates the area of study. Plant anatomy is study of the structure of plants; veterinary anatomy is study of structure of animals; equine anatomy is study of structure of horses. Study of structure of the human body is called human anatomy.
The scope of the subject has widened very much and several subdivisions are now studied. These subdivisions include:
  • Gross anatomy or morphological anatomy or macroscopic anatomy: Study of structures which can be seen by naked eye (Greek.macro=large; skopein=to watch; morphe=form/shape);
  • Microscopic anatomy or histology: Study of structures which can be seen only on magnification, like under a microscope. Histology can also be defined as study of tissues, since tissues are microscopic. Further subdivision is ultrastructural anatomy which is study of tissues using higher magnification like the electron microscope (Greek.micros=small; histos=tissue);
  • Cytology: Study of details of the structure of cells (Greek.kytos=cell);
  • Embryology or developmental anatomy: Study of growth and development of body structures before birth (Greek.embryo=to grow);
  • Regional anatomy or Topographical anatomy: Study of various structures in relation to their location and relationship to the adjacent structures;
  • Systemic anatomy: Study of the various organ systems of the body;
  • Cadaveric anatomy: Study of dead and preserved bodies;
  • Living anatomy: Study of anatomy in a living individual by using simple techniques like palpation, percussion and auscultation or higher techniques like endoscopy, radiography and electrography.
It can well be seen that areas like radiological anatomy and clinical anatomy form part of living anatomy.
  • Functional anatomy: Study of the structural basis of the functions of various structures and the interrelationships of various organ systems;
  • Applied anatomy or clinical anatomy: Study of aspects of anatomy that play a role in disease, diagnosis of disease and treatment;
  • Cross-sectional anatomy: Study of body structures with special reference to cross-sections of the body at different levels;
  • Surface anatomy: Study of surface projections of internal structures with special reference to accessing them easily (the name topographic anatomy can also be applied to this since the internal topography is marked on the surface);
  • Radiological anatomy or imaging anatomy: Study of structures as they appear in imaging pictures like X-rays, CT scans, ultrasound images and MRI scans;
  • Histochemistry: Study of chemical processes that take place in cells and tissues;
  • Experimental anatomy: Study of factors which influence and control the structure and functions of different parts of the body;
  • There are areas which are closely allied to anatomy but also deserve separate specialisation. These include:
    • Genetics: Study of chromosomes and genes;
    • Anthropology: Study of the features of different groups and races of human. This is now specifically called physical anthropology, since areas like social and economic anthropology have also evolved.
 
DESCRIPTIVE TERMS
Study of ‘Anatomy’ is fundamental and essential to all subsequent studies in medical education. Anatomical terms are used in every other speciality of medical curriculum. Terms like ‘in front’, ‘behind’, ‘above’, ‘below’, and so on, which are used in describing structures are not scientific terms and can lead to ambiguity if improperly used. Hence, scientific and definitive terms are needed.
 
Anatomical Position
While describing structures of the human body, it is necessary to have uniformity of terms to avoid confusion and ambiguity. Hence, all descriptions are done with reference to a standard position called the normal anatomical position (Fig. 1.1). The human body is regarded as standing upright, eyes looking directly forwards (to a distance), feet parallel to each other and toes directed forwards, with the arms held by the sides of the body and with the palms facing forwards. The cadaver, during dissection may be lying on its back, on its side or on its face; whatever, it should be assumed to be in anatomical position and all descriptions and studies made with reference to this position. Similarly, the living patient may be in any position during examination or treatment; but all references to body structures should be in anatomical position.
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Fig 1.1: Normal anatomical position
Whether it is dissection of the cadaver or examination of a living individual, two other positions frequently adopted are the supine and prone positions. In the supine position, the individual lies on the back with the upper limbs placed by the side of the trunk, palms facing upwards and feet together. In the prone position, the individual lies on the chest and belly with the face downwards and upper limbs on the side of the trunk.
 
Planes of the Body
As the human body is a three-dimensional (3D) structure, three perpendicular planes are described.
  • The plane passing vertically through the midline of the body, so as to divide the body into right and left halves, is called the median plane. It is also called the mid-sagittal plane, since it is parallel to the sagittal suture of the skull (Fig. 1.2);
  • Vertical planes to the right or left of the median plane, and parallel to the latter, are called paramedian or parasagittal planes (or plainly the sagittal planes) (Fig. 1.2);
  • The vertical plane placed at right angles to the median plane, but dividing the body into anterior and posterior parts, is called a coronal plane or a frontal plane (Fig. 1.3).5
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    Fig 1.2: Scheme showing median and sagittal planes
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    Fig 1.3: Scheme showing a coronal or frontal plane
    It is parallel to the coronal suture of the skull;
  • Planes passing horizontally across the body, at right angles to both the sagittal and coronal planes and dividing it into upper and lower parts, are called transverse or horizontal planes (Fig. 1.4). In the case of a limb, a transverse section is any section at right angles to the long axis of the limb. Similarly, the transverse section of an organ is at right angles to the long axis of the particular structure.
  • An oblique plane is at any other angle.
 
Terms of Location and Relationship (Fig. 1.5)
To describe various structures with reference to each other, several terms are required. Of these, three pairs of terms are basic and important. These are as follows:
  1. Anterior—posterior: Anything nearer or closer to the front is anterior; anything nearer or closer to the back is posterior (Fig. 1.5).
  2. Superior—inferior: Anything nearer or closer to above is superior (nearer the top of head); anything nearer or closer to below is inferior (nearer the sole of feet) (Fig. 1.5).
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    Fig 1.4: Scheme showing a horizontal or transverse plane
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    Fig 1.5: Surfaces of body
  3. Medial—lateral: Anything nearer or closer to the centre or the midline of the body is medial; anything farther from the midline is lateral (Latin.medius=middle; latus=side) (Fig. 1.5).
The vertical plane passing through the midline of the body, as already been described, is the median plane (Fig. 1.2). Any structure lying in the median plane is described to be median in position.
It can be clearly seen that the above mentioned three sets of terms correspond to the three fundamental perpendicular planes of the body.
Structure A in figure 1.6 is nearer to the front of the body as compared to structure B; hence A is said to be anterior to B and B is posterior to A. If Z is taken into account, Z is anterior to b and posterior to A. Structure C lies nearer the upper end of the body as compared to structure D; hence C is said to be superior to D and D is inferior to C.
When a structure lies in the median plane it is said to be median in position. As shown in the figure 1.7, structure E lies nearer to the median plane than structure F; hence E is said to be medial to F and F is lateral to E.6
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Fig 1.6: Scheme to explain the terms anterior—posterior, superior—inferior
 
Other Terms of Description
There are several other terms which are used frequently to indicate location, shape, size and relations of a structure. The following list shows these terms.
  • Ventral: Closer to or on the belly side of the body (Latin.venter=belly);
  • Dorsal: Closer to or on the back surface of the body (Latin.dorsa=back).
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Fig 1.7: Scheme to explain the terms medial, lateral and median
The terms cranial and caudal are also used. Anything closer to the head or towards the head is cranial (cranium — head; Greek.kranion=skull) and anything closer to or towards the tail portion is ‘caudal’ (Latin.cauda=tail). Cephalic is a term used as a substitute to cranial and means towards the head. These terms are routinely used in embryology and it is preferable to use them in gross anatomy too.
With regard to the limbs of the body, the terms superior and inferior are sometimes replaced by another set of terms: proximal and distal (Fig. 1.1). Proximal is anything closer to the root (or point of origin; Latin.proximus=nearest) and distal is anything away from the root (more distant; Latin.distare=to be distant). This can be noted in the naming of the phalanges of the hands; the phalanges close to the base of the fingers are proximal, those close to the tips are distal and those between the two are middle.
There are also other sets of terms used with reference to the limbs. As the palms face forwards in the normal anatomical position, the upper limb can be described to have a medial border (Fig. 1.1) (one that is close to the body trunk) and a lateral border (Fig. 1.1) (one that is away from the body trunk).
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Figs 1.8A and B: Anatomical terms—terms of location
7Since the ulna bone of the forearm is on the medial aspect and the radius bone on the lateral aspect, the medial and lateral borders are called the ulnar and radial borders. A similar situation can be seen in the lower limb too. The tibia of the leg is medial and the fibula is lateral; hence, the medial border is called the tibial border and the lateral border is the fibular border. The anterior surface of the hand (one related to the palm) is palmar or volar; the inferior surface of the foot is plantar; the opposites of both these, namely, the posterior surface of hand and the upper surface of foot are dorsal.
 
Terms of Laterality
These are terms which indicate the left or right sides or both.
  • Unilateral: Only one side. Structures which occur only on one side of the body are unilateral. An example is the spleen that occurs on the left side of the body
  • Bilateral: Both sides of the body. Structures which have both right and left members are bilateral. Example is the kidney
  • Ipsilateral: Same side of the body. Right hand and right foot are ipsilateral
  • Contralateral: Opposite side of the body. Right hand and left foot are contralateral.
 
Terms of Size and Shape
While describing structures, it is essential to compare their sizes and even shapes. Thus terms which specifically talk about sizes and shapes of structures are also frequently used.
  • Great/magnus: Indicating larger size/longer length/bigger appearance
  • Small/parvus: Indicating smaller size/shorter length/smaller appearance
  • Greater/major: Indicating larger size but used in comparison of two identical or related structures
  • Lesser/minor: Indicating smaller size but used in comparison of two identical or related structures.
When the term ‘magnus’ is used, there need not essentially be another structure befitting the ‘parvus’ description. But, when the term ‘major’ is used, there is usually another related structure that befits the ‘minor’ description.
 
Terms of Movements (Figs 1.9 and 1.10)
The human body is a jointed structure and movements can be seen to occur at these joints. Various movements have been given separate names.
  • Flexion—extension: To flex is to bend or make an angle; flexion is thus bending. To extend is to stretch or straighten; extension is straightening from the flexed position. Flexion usually brings two anterior (or ventral) surfaces closer to one another; extension is back to normal from flexed position (Figs 1.9A to D).
  • Abduction—adduction: To abduct is to take away or lead away (ab=from, duco=lead); abduction is therefore draw away from median plane or midline. To adduct is to bring closer (ad=to, duco=lead); adduction is drawing closer to the median plane or midline (Figs 1.10A and B).
  • Medial rotation-lateral rotation: Medial (internal) rotation is turning inwards and lateral (external) rotation is turning outwards (Fig. 1.10D).
Movements occur around axes. As for any three-dimensional structure, three perpendicular axes can be defined for the human body too. These are the transverse axis, the longitudinal axis and the antero-posterior axis. Flexion-extension movements occur around the transverse axis and in the sagittal plane. A typical example can be seen in the elbow joint; when the anterior aspects of the upper arm and the forearm come close to each other, it is flexion; when the anterior aspects move away and the limb straightens out, it is extension. Abduction-adduction movements occur around the antero-posterior axis. Example of this can be seen in the shoulder joint; when the limb is lifted and drawn away from the trunk, it is abduction; when the limb is brought back to hang by the side of the trunk, it is adduction.
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Figs 1.9A to D: Scheme to explain flexion and extension at different parts of the body
Rotational movements occur around the longitudinal axis. Example is the upper limb rotating at the shoulder joint. During medial rotation, the anterior surface turns inwards and the lateral (radial) border turns to face forwards; during lateral rotation, the posterior surface turns inwards and the lateral border turns to face backwards.
When extension proceeds beyond straightening, there is an attempt of posterior or dorsal aspects coming into contact; this is called hyperextension. It can well be seen in the wrist. Bending the wrist in such a way to bring the palm closer to the anterior aspect of forearm is flexion. Taking the hand back to its normal position is extension. If the wrist is further extended in an attempt to bring the dorsum of hand closer to the posterior aspect of forearm, it is hyperextension.
Circumduction (circum=around) is a combination of all movements but in sequence. Flexion, abduction, extension and adduction occur in sequence; a cone is thus described. Rotational movements accompany the other movements and therefore all the axes are involved.9
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Figs 1.10A to H: Terms of movement A. Abduction-adduction B. Medial rotation-lateral rotation C. Pronation-supination D. Opposition-reposition E. Eversion and invasion F. Dorsiflexiion-plantarflexion G. Retrusion-protrusion H. Elevation-depression
10
 
Special Terms of Movements
Certain special terms are used to describe special movements.
Pronation-supination is one such set (Fig. 1.10C). To pronate is to flex. This term was originally applied to indicate bending of the entire body forwards, when the individual is facing downwards or is prone. The terms prone and supine are still used with reference to the position of the entire body. As already seen, supine is lying on the back and prone is lying face down. However, the terms ‘pronation’ and ‘supination’ are being used in relation to the forearm. To pronate the forearm is to turn it in such a way that the palm faces downwards when the forearm is resting on a table or on the lap. This, if in normal anatomical position, will mean palm facing backwards. Supination is when the palm is facing upwards while the forearm rests on the table. This is equivalent to the limb hanging by the side of the trunk with the palm facing forwards.
Abduction-adduction movements occur at the wrist. The hand is angulated in relation to the forearm; abduction which carries the hand towards the radial side (the angle between the thumb and forearm becomes less than 180 degrees) is otherwise called radial deviation; adduction which carries the hand towards the ulnar side (the angle between the little finger and the forearm is less than 180 degrees) is called ulnar deviation.
The thumb has a movement that goes by a different name. It is possible to touch the tip of the thumb to the tips of the other fingers. This movement is called opposition (Fig. 1.10D). Pinching and lifting a teacup by its handle are movements when opposition comes into play. Movement of thumb back to anatomical position from opposition is reposition.
In the lower limb, the foot is capable of going through another set of movements. These are the inversion-eversion movements. When the lateral border of the foot is placed on the ground and the medial border raised, the sole faces inwards; this is inversion. When the opposite occurs, that is, when the medial border placed on the ground and the lateral border raised, the sole faces outwards; this is eversion (Fig. 1.10E).
The movement at the ankle which causes the dorsum of the foot to come closer to the leg is actually extension and is frequently referred to as dorsiflexion. The opposite movement where the dorsum moves away from the leg is the plantarflexion (Fig. 1.10F).
Protraction—retraction are terms used with reference to the lower jaw. To protract (pro=forwards, traho=pull) is to move forwards; protraction of the lower jaw is pushing of the jaw forwards in relation to the upper jaw and rest of the face. To retract is to move backwards. Retraction of the lower jaw is drawing it back. Protrusion andretrusion are terms which can be substituted for protraction and retraction respectively (Fig. 1.10G).
Elevation raises a part or structure and depression brings it down (Fig. 1.10H).
 
Other Subdivisions of Anatomy
Apart from the subdivisions of Anatomy mentioned above (and which a medical student would frequently encounter), there are also other subdivisions. The knowledge of Anatomy is necessary for several areas of work and at various levels of importance. Thus use of anatomical knowledge when and where required has given rise to various other subdivisions which a medical professional may or may not have an opportunity to come across.
  • Surgical anatomy: Study of structures with emphasis on direct, practical significance in surgical practice;
  • Relief anatomy: Study of the various areas and structures in relation to the external features and relief of the body (outline appearance of the body);
  • Sports anatomy: Study of the effects of various sports on the structures of the body;
  • Anatomical anthropology: Study of anatomy of human with differing traits (due to race, bodily constitution, habitat);
  • Dynamic anatomy: Study of the structure and function of the locomotor apparatus and supportive organs of locomotion (this has extensive importance in sports and physical culture);11
  • Plastic anatomy: Study of the external form and proportions of the body as required for artists and sculptors;
  • Morbid anatomy or pathological anatomy: Study of structures in a sick individual and the morbid changes in such organs;
  • Age anatomy: Study of the effects of ageing on various structures of the body;
  • Gerontic anatomy: Study of structures in relation to the degenerative changes due to old age; this is similar to age anatomy, but relates to old age and not to anatomical changes until the fourth or fifth decade of life (Greek.geron/gerontos=old man);
  • Phylogeny: Study of the human individual and his/her development in relation to the developmental processes of lower life forms (Greek.phylon=genus; genesis=development);
  • Ontogeny: Study of the development of the individual throughout life(Greek.onthos=being);
  • Teratology: Study of malformations (Greek.teras/teratos=monster; logos=study/science).
 
STRUCTURES CONSTITUTING THE HUMAN BODY
While describing the various structures of the human body, it is essential to understand that most human beings have the same pattern of structures. This pattern can be called the norm or the commonest anatomy seen in most individuals.
In a few individuals, alterations/modifications to the commonest can be seen. These are described as variations or anomalies (Greek.anomalos=irregular). The basic difference between a variation and an anomaly is that, a variation does not disturb the function but an anomaly usually produces some compromise of the function.
 
Main Subdivisions of the Human Body (Fig. 1.11)
For convenience of description the human body is divided into a number of major parts. These parts have specific anatomical names and it can be seen that these names (and/or terms) are repeatedly used during the study of human body. These names have also been used in describing various structures related to the concerned body parts, either in complete form or in part.
The uppermost part of the body is the head (caput). The face (facies) is part of the head. Below the head, is the neck (collum). In the head, the following areas can be identified: forehead (frons), highest point (vertex), back of head (occiput) and temples (tempora). Below the neck, is the region called the chest. In anatomical terminology the chest is referred to as the thorax. The thorax is in the form of a bony cage within which the heart and lungs lie. Below the thorax, is the region commonly referred to as ‘stomach’ or ‘belly’. The correct name is abdomen. The abdomen contains several organs of vital importance to the body. Traced downwards, the abdomen extends to the hips. That part of the abdomen present in the region of the hips is called the pelvis. The thorax and the abdomen together form the trunk (truncus). Back (dorsum) is that part of the trunk which is the posterior aspect of both the thorax and the abdomen. The lowest part of the trunk around the urinary, reproductive and anal openings is the perineum.
Attached to the trunk, there are the upper andlower limbs, or the upper and lower extremities. The upper limb is divided into the arm (brachium), the forearm (antebrachium) and the hand (manus). The lower limb is divided into the thigh (femoral), the leg (crus) and the foot (pes).
Taking the whole body into account, we can say that the body is made of the axial and the appendicular regions. The axial region is the one that makes up the main axis of the body and consists of the head, neck and trunk. The appendicular region (appendix or appendage= something that is added) consists of the limbs.12
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Figs 1.11A and B: Parts of human body A. Anterior view B. Posterior view
 
Structural Components
The human body has several different kinds of structures.
Their physical characteristics are also different. How then can these be named? Certain general terms are used to denote certain parts or structures or the whole of structures:
  • Organism: The living being that is capable of growing and multiplying; it is also capable of exchanging substances with its environment;
  • Tissue: A group of similar cells which have specific morphological and biochemical properties; sometimes, it can have cells of other types to give support or additional advantage;
  • Organ (Greek.organon-tool): A part of the body that serves as an instrument for adaptation of the individual/ organism with the environment; the organ is an integral part of the whole and has its own structure, function, position and development; it cannot exist separately outside the individual/organism;
  • Permanent/definitive organs: Those characteristic of the adult anatomy and persist throughout life;
  • Temporary/provisional organs: Those which appear in a particular stage of development and then disappear;
  • Morpho-functional organs: Those which themselves are made up of many structures and tissues but form part of some other larger organs; example of this is a nephron which by itself is a part of the kidney;
  • System of organs/organ system: The collection of homogenous organs marked by a common structure, function and development; it can be defined as a morphological and functional assemblage of organs; examples are bone system, muscular system and digestive system;
  • Apparatus: The collection of heterogenous organs which are united for the performance of a common function; example is the endocrine apparatus, where endocrine glands with different structural and developmental properties are clubbed because of a common function, namely, production of hormones; the term apparatus is also used sometimes to denote smaller parts/structures of an organ marked by a definitive functional importance; example of such usage can be seen in phrases like the receptor apparatus of the kidney, the receiving apparatus of the neuron etc;
  • Super system: The functional togetherness of two or more organ systems for the sake of bringing about 13certain functions; example is the locomotor system; though called a system, it actually is a supersystem because the muscular system, the skeletal system and some parts of the nervous system together constitute the locomotor system and this togetherness is essentially for locomotor functions.
As we study various parts of the body, we notice that several different kinds of structures are present in a given organ or region or part. These structures have different physical and functional qualities.
The basic framework of the body is provided by a large number of bones that collectively form the skeleton. As bones are hard they not only maintain their own shape, but also provides shape to the part of the body within which they lie.
In some situations (e.g., the nose or the ear) part of the skeleton is made up, not of bone but of, a firm but flexible tissue called cartilage.
Bones meet each other at joints, many of which allow movements to be performed. At joints, bones are usually united to each other by fibrous bands called ligaments.
Overlying (and usually attached to) the bones are the muscles. Muscles are what the layman refers to as flesh. In the limbs, muscles form the main bulk. Muscle tissue has the property of being able to shorten in length. In other words muscles can contract, and by contraction they provide power for movements. A typical muscle has two ends, one (traditionally) called the origin, and the other called the insertion. Both ends are attached, usually, to bones. The attachment of a muscle to bone may be a direct one, but quite often the muscle fibres end in a cord like structure called tendon. Tendons convey the pull of the muscles to the concerned bones and are very strong structures. Sometimes a muscle may end in a flat fibrous membrane. Such a membrane is called an aponeurosis.
When we study a limb, we find that the muscles within it are separated from skin, and from each other, by a tissue in which fibres are prominent. Such tissue is referred as fascia. Immediately beneath the skin the fibres of the fascia are arranged loosely and this loose tissue is called superficial fascia. Over some parts of the body the superficial fascia may contain considerable amounts of fat. Deep to the superficial fascia the muscles are covered by a much better formed and stronger membrane. This membrane is the deep fascia. In the limbs, and in the neck, the deep fascia encloses deeper structures like a tight sleeve. The major difference between the superficial fascia and the deep fascia is that the latter has closely packed fibres and appears sheet like.
Membranes similar to deep fascia may also intervene between adjacent muscles forming intermuscular septa. Such septa often give attachment to muscle fibres.
Running through the intervals between muscles (usually in relation to fascial septa) are the blood vessels, lymphatic vessels, and nerves. Blood vessels are tubular structures through which blood circulates. The vessels that carry blood from the heart to various tissues are called arteries. Those vessels that return this blood to the heart are called veins. Within tissues, arteries and veins are connected by plexuses of microscopic vessels called capillaries.
Lymphatic vessels are delicate, thin walled tubes. They are difficult to be seen by naked eye. They often run alongside veins. Along the course of these lymphatic vessels small bean-shaped structures are present in certain situations. These are the lymph nodes. Lymphatic vessels and lymph nodes are part of a system that plays a prominent role in protecting the body.
Running through tissues, often in the company of blood vessels, are also solid cord like structures called nerves. Each nerve is a bundle of a large number of nerve fibres. Each nerve fibre is a process arising from a nerve cell (or neuron). Most nerve cells are located in the brain and in the spinal cord. Nerves transmit impulses from the brain and spinal cord to various parts and tissues of the body. They also carry information from the parts and tissues to the brain. Impulses passing through nerves are responsible for contraction of various muscles and for secretions by various glands. Sensations like touch, pain, sight and hearing are all dependent on nerve impulses travelling through the nerve fibres.
Bones, muscles, blood vessels are seen in all parts of the body. In addition to these, organs are seen in some parts of the body. Organs are otherwise called viscera (Singular.viscus; plural.viscera; Latin.visko=soft; other name: splanchna) and are usually seen in the cavities of thorax and abdomen. Some of the viscera are solid (e.g., the liver or the kidney), while others are tubular (e.g., the intestines) or sac like (e.g., the stomach). The viscera are grouped together in accordance with their functions to form various organ systems. Some examples of organ systems are the respiratory system responsible for providing the body with oxygen, the alimentary ordigestive system responsible for the digestion and absorption of food, the urinary system responsible for removal of waste products from the body through urine and the genital system which contains organs concerned with reproduction.14
Multiple Choice Questions
1. Study of internal structures using CT scans and MRI images is:
  1. Internal anatomy
  2. Applied anatomy
  3. Imaging anatomy
  4. Experimental anatomy
2. The term to indicate a structure closer to root is:
  1. Distal
  2. Proximal
  3. Cephalic
  4. Rostral
3. All of the following are terms of movement except:
  1. Contralateral
  2. Abduction
  3. Hyperextension
  4. Circumduction
4. Pronation of the forearm makes the palm:
  1. Face upwards
  2. Face backwards
  3. Move medially
  4. Spread the fingers
5. Structures which convey the pull of a muscle to the attached bone are:
  1. Nerves
  2. Tendons
  3. Ligaments
  4. Tendon sheaths
ANSWERS
1. c
2. b
3. a
4. b
5. b