Skeletal System

Skeletal System

The skeletal system of human is made up of two parts:
1. Axial skeleton
2. Appendicular skeleton

1. Axial skeleton

The skeleton, which makes the main axis of the body is called axial skeleton. Skull, vertebral column and bones of chest comes under it. There are 80 bones in axial skeleton.

(i) Skull
There are 29 bones in it. Out of these, 8 bones jointly protect die brain of the human. The structure made up of these bones is called forehead. All the bones of the forehead remain joined strongly by the sutures. There are 14 bones in addition to this which form the face. Six ear ossicles and one hyoid bone.

Vertebral Column : The vertebral column of the human is made up of 33 vertebra. All the vertebra are joined by intervertebral disc. Vertebra is made flexible by these intervertebral disc. We divide the whole vertebral column into the following parts.

» Its first vertebra which is called atlas holds the skull.

Functions of vertebral column:
1. Holds the head
2. It provides the base to the neck and body.
3. It helps the human in standing, walking etc.
4. It provides flexibility to the neck and body by which a human can move its neck and body in any direction.
5. It provides protection to spinal cord.

2. Appendicular skeleton

The following are the parts of it -
(i) Foot bones — Both hands and feet have 118 bones.
(ii) To hold the forelimb and hind limb on the axial skeleton in human there are two girdles.
» The girdle of forelimb is called pectoral girdle and girdle of hindlimb is called pelvic girdle.
» Pectoral girdle joined with forelimb is called humerus and the bone from pelvic girdle join to hindlimb is called femur.

Functions of the skeletal system
1. To provide a definite shape to the body.
2. To provide protection to soft parts of the body.
3. To provide a base to the muscles for joining.
4. To help in respiration and nutrition.
5. To form Red Blood Corpuscles.

» The total number of bones in a human's body — 206
» The total number of bones during childhood — 300
» The total number of bones of head — 29
» The total number of bones in vertebral column, initially - 33
After development - 26 (5 sacral fuse into 1 and 4 caudal fuse into 1)
» The total number of bones of ribs 24
» The largest bone of the body Femur (bone of thigh)
» The smallest bone of the body Stapes (bone of ear)
» Foramen Magnum is an aperture found in the skull.