In this course we will describe the introduction to human anatomy to students who begin their January in studying medicine, dentistry, pharmacy, nursing, physical and sports medicine. Human anatomy is concerned with the study of the structures of the different parts of human body that can be seen with the naked eye (gross anatomy) and the relations of these structures to each other.
Methods of teaching human anatomy
First method is to study body systems separately to give a whole picture of the structures forming each system.
Second method is to study each region of the body and examine all the structures found in it and the relations of these structures to each other. It is the anatomy that surgeons need to know so that they are always aware of the structures found in the area of the body in which they specialize.
The anatomical position: a standard position in which the different regions, organs and structures of the human body are described. It is the position when the person is:
1. Stand upright
2. The neck is extended
3. The face is directed forwards
4. The arms hang at the sides and the palms of the hand are directed forwards.
5. The feet spread on the ground.
Regions of the human body:
1. The head: surrounds the brain. It includes the facial structures.
2. The neck: the constriction following the head.
3. The upper limb: hangs at the sides of the thorax. It includes the shoulder region, the arm, the forearm and the hand.
4. The thorax: its bones surround the heart and the lungs.
5. The abdomen: contains the abdominal organs and separated from the thorax by the diaphragm.
6. The pelvis: the lower part of the abdominal cavity.
7. The lower limb: includes the gluteal region, the thigh, the leg and the foot.
These terms are used to describe the relations of the different structures and organs to each other.
1) Median: the structure which lies at the midline of the body is a median structure e.g. vertebral column.
2) Medial and lateral: describe the relation of two structures or points to each other. The structure which lies close to the midline is called medial and the structure which lies away from the midline is called lateral.
3) Anterior and posterior: describe the relation of two structures or points to each other. The structure which lies near to the front of the body is called anterior while that which lies away from the front of the body is called posterior.
4) Superior and inferior: describe the relation of two points to each other. The point which lies near to the upper part of the body is superior or upper and that which lies away from upper part is inferior or lower.
5) Deep (internal) or superficial (external): These terms are used to describe the relations of two points. The point near to the central axis of the body is called deep (internal) and the point away from the center or nearer to body wall is superficial or external.
6) Palmar or dorsal: These terms are used for the hand. The anterior surface of the hand is palmar while its posterior surface is dorsal.
7) Planter or dorsal: These terms are used for the foot. The surface which lies on the ground is planter while the surface which is directed upwards is dorsal.
8) Proximal or distal: These terms are used for the limbs to describe the relation between two points one near the trunk called proximal and one away from the trunk called distal e.g. The shoulder is proximal to the elbow. The elbow is proximal to the wrist. The wrist is distal to the elbow.
Planes of human body
1) Coronal: it is the plane which divides the body into anterior and posterior halves.
2) Sagittal plane: it is the plane which passes antero-posteriorly through the body dividing it into right and left halves. If this plane divide the body into two equal halves it is called mid-sagittal plane. If it divides the body into non-equal parts it is called para-sagittal plane.
3) Horizontal (transverse) plane: it is the plane which divides the body into upper and lower parts. This plane may pass through the level of any of the vertebrae e.g. level of first lumbar vertebra (L1).
Terms of movements
1) Flexion and Extension:
Flexion: is the movement which approximates the ventral (anterior) surfaces to each other.
Extension: is the movement which moves the ventral surfaces away from each other.
There is an exception for this rule; in the lower limb flexion moves the posterior surface near to each other and the reverse occurs in extension.
In the trunk there are two types of flexion; forward flexion and lateral flexion.
2) Adduction and abduction:
Adduction: is the movement which brings the limb (upper or lower) towards the midline of the body.
Abduction: is the movement which moves the limb away from the midline of the body.
3) Medial rotation and Lateral rotation:
Medial rotation: is the movement which rotates the limb (upper or lower) to bring its anterior surface towards the midline.
Lateral rotation: is the movement which rotates the limb (upper or lower) to bring its anterior surface away from the midline.
4) Circumduction: It is a combination of flexion , abduction , extension and adduction in succession. It occurs at the shoulder and hip joints .
5) Elevation and depression: as occurs in the shoulder joint or in the movement of the mandible (lower jaw).
6) Protraction and Retraction:
Protraction: forward movement of the shoulder girdle as in pushing or of the mandible to bring the lower teeth in front of the upper teeth.
Retraction: is the backward movement of the shoulder girdle or of the mandible to bring the lower teeth opposite the upper teeth.
7) Inversion and eversion: occurs in the foot only:
Inversion: is the movement which turns the sole of the foot to the inner side or medially (inwards).
Eversion: is the movement which turns the sole of the foot to the outer side or laterally (outwards).
8) Supination and pronation: occurs in the forearm.
Pronation is the movement which turns the palm of the hand backwards.
Supination is the movement which turns the palm of the hand forwards.
9) Opposition: restricted to the thumb and it is the movement which brings the palmar surface of the distal phalanx of the thumb with those of the other fingers .