The hip joint consists of the rounded off head of the hip and the shell-like hip joint socket. It forms the flexible connection between the legs and the torso.
The contact surfaces of the two bony structures are covered with a soft layer of cartilage tissue. Mucous membrane formed by the synovial fluid assures feeding the cartilage and lubricating the joint. Since more than half of the head of the femur lies within the bony-connective tissue socket, one speaks of a ball and socket joint.
A circular lip of the joint (labrum) made of cartilage forms the edge of the bony socket.
The joint capsule is strengthened by strong ligament structures. The joint capsule, ligaments, and the surrounding musculature hold the joint in its position.