The joints and their significance to the movement
The joint is the location at which the bones meet each other , and they allow the movement between the bones , It is the point where two bones meet , The joints hold the bones together , they give the stability at the same time , they give the skeleton mobility .
The bones act as the levers that can be moved by the skeletal muscle to which they are attached , The human skeleton is made up of different shaped bones that align with each other , The point where the bones align is called a joint .
The joints provide the mechanism that allows the body to move , They allow the movement to occur , so that we can sit , walk , run , ……………..etc , The joint moves when the muscles crossing it contract , It facilitates the motion and allows the flexibility .
The types of the joints
The joints are classified according to their degree of the movement , There are three types of the joints which are the immovable joints , the slightly movable joints and the freely movable joints .
The immovable joints do not allow any movement as the joints between the bones of the skull .
The slightly movable joints allow the movement in one direction only as the knee and elbow joints .
The freely movable joints allow the movement in all the directions as the shoulder , the wrist and the thigh ( hip ) joints .
Note : The bones that in contact with these joints are covered with a delicate layer of a transparent smooth cartilaginous substance which allow the movement of the bones easily with less friction , They contain a synovial fluid which facilitates the sliding of the cartilages that cover the tips of the bones .