Biology · Support and Movement

Joints are locations in the body where bones meet. The hinge joints of the body include the elbow, knee, interphalangeal (IP) joints of the hand and foot, and the tibiotalar joint of the ankle.

An immovable/fixed/fibrous joint is an articulation between bones in which no movement occurs. It is also referred to as synarthrotic (meaning immovable). Immovable joints include skull sutures, the articulations between the teeth and the mandible, and the joint found between the first pair of ribs and the sternum.

Slightly movable joints permit some movement but provide less stability than immovable joints. These joints can be structurally classified as cartilaginous joints, as bones are connected by cartilage at the joints. Slightly movable joints include the distal joint between the tibia and the fibula and the pubic symphysis of the pelvic girdle.

A hinge joint is a type of synovial/freely movable joint that exists in the body and serves to allow motion primarily in one plane. The hinge joints of the body include the elbow, knee, interphalangeal (IP) joints of the hand and foot, and the tibiotalar joint of the ankle.

The ball and socket joint is a type of synovial/freely movable joint. It is a joint with a rounded bone, referred to as a ball, moving within a depression of another bone called the socket. The hip and shoulder joints are examples of ball and socket joints.