Question

What is a joint? Describe various types of joints with suitable examples.

Answer 1

A joint is a structural arrangement where two bones articulate. The joints are essential for the movement of different skeletal structures. The movability in joints varies. On the basis of movability, joints are divided into three groups, namely, fibrous joints, cartilaginous joints and synovial joints.

1. Fibrous joints: They do not allow any movement because the bones are firmly fixed together by strong collagen fibres. Example: skull bones and attachment of tooth with the socket in jaws.

2. Cartilaginous joints: The two bones are joined together with the help of a disc or pad of white fibrous cartilage. They show only slight movement because the disc restricts the movement. Example: vertebral column, sternum, ribs, etc.

3. Synovial joint: These are freely movable joints which allow movement in one or more directions. The bones are covered by synovial membrane and cavity is filled with synovial fluid. These are further of six types.

A. Ball and socket joint in the shoulder and hip joint.

B. Hinge joint in elbow and knee joint.

C. Pivot joint between radius and ulna below the elbow.

D. Gliding joint in wrist and tarsals.

E. Saddle joint between carpals and metacarpals.

F. The condyloid joint in fingers.