How does the hip joint work?
The hip is a ball-and-socket joint that helps you move your legs during everyday activities such as walking and going up and down stairs. It has a good range of movement but it’s very stable and rarely dislocates, even after high-impact trauma.
The ball of the joint, which is at the top of the bone in your upper leg (the femur), is called the femoral head, and the socket created by the hollow of your pelvis is called the acetabulum.
The joint is surrounded by a tough, fibrous sleeve called the capsule, which helps to hold the bones together. The capsule is lined by the synovium, which produces a fluid (synovial fluid) that nourishes the cartilage and lubricates the joint. The hip joint is moved by a number of muscles that allow you to rotate your hip and walk.