Hip Bones and Joints
The hip, like the shoulder, is a ball and socket joint. It is formed by the head of the femur (thigh bone), which sits in the acetabulum, a part of pelvis. The head of the femur is large (ball) and the acetabulum (socket) is shallow. This makes the joint unstable but simultaneously allows for greater mobility.
The bony joint surfaces of the head of the femur and acetabulum are covered with articular cartilage. The articular cartilage has a smooth and shiny surface that allows the ends of the bones to slide freely over each other.