THE SKELETON

Posted by DAM on February 10, 2012 in The Skeleton | Short Link
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THE SKELETON

(Fig. 4)

The human skeleton, is described in two main parts:

a)  The axial skeleton which includes the skull, the vertebral

column, the ribs and the sternum.

b)  The appendicular skeleton which includes the bones of

the appendages (upper and loweriimbs) and their girdles (pectoral and pelvic girdles).

Tilt SkalS together with the mandible forms the skeleton of the head and face but without the mandible, it is called the cranium.

The vertebral column (Fig. 5) consists of a series of bones called vertebrae. The bodies of these vertebrae articulate with one another by means of fibrocartilaginous intervertebral discs.

The vertebral column comprises five distinguished regions, each has a more or less fixed number of vertebrae. These are: 7 in the cervical region, 12 in the thoracic region, 5 in the lumbar region, 5 in the sacral region and 4 in the coccygeal region.

The thoracic vertebrae are characterised by having ribs attached to them. Together with these ribs, costal cartilages and sternum, they form the skeleton of the thoracic cage.

The sacral vertebrae are characterised by being united together into a single triangular bone called the sacrum. Together with the two hip bones, it forms the skeleton of the pelvis.


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The skeleton of the upper limb resembles that of the lower limb in its general plan, but differs in its detailed structure and in its mode of attachment to the axial skeleton

The skeleton of each limb (upper or lower) consists of three segments: proximal, intermediate and distal

         The proximal segment consists of one bone the humerus in the upper arm – the femur in the thigh

         The intermediate segment consists of two bones the radius and ulna in the forearm – the tibia and fibula in the leg

         The distal segment consists of three sets of bones:

1  A series of small bones: the carpal bones in the hand -the    tarsal bones in the foot.

2      Five elongated bones: the metacarpals in the hand the metatarsals in foot.

3      The phalangeal bones: these are three in each finger or toe except the thumb or the big toe in which case the> are only two

The pectoral (or shoulder) girdle consists of the clavicle and the scapula. It articulates with the axial skeleton anteriorly at the sternoclavicular joint. There is a wide range of movement of the upper limb on the shoulder girdle.

The pelvic girdle consists of the two hip bones. They articulate with the axial skeleton posteriorly at the sacro -iliac joints. The range of movement in the lower limb is less than that in the upper limb

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