Joints and their Types

Joints and their Types The point at which two separate bones meet is called a joint.

The point at which two separate bones meet is called a joint. There are four types of joints in the human body. They are: Ball and socket joint: One end of a bone is rounded and ball-like, and fits into a cup-like depression of the other bone. This joint provides movement in any direction. Shoulder joints and hip joints are examples. In the shoulder joint, the head of the humerus fits into a socket of the shoulder girdle. In the hip joint, the large ball-like head of the femur fits into the deep socket of the hip girdle. Hinge joint: This joint moves like a hinge in one plane only, just like the hinge of a door. The elbow joint between the humerus and the ulna. The joints between the bones of the fingers and toes, and less perfectly, the knee joint. Hinge joints usually give sufficient power, because there is less danger of twisting at the joint.

Pivot joint: One bone rotates over a pivot-like end of the other bone. The skull rotates on the upper end of the back bone. Fixed Joint: In this joint, no movement is possible between the two bones. The sutures between the bones of the cranium are an example.