The thighbone (femur) and the pelvis (acetabulum) join to form the hip joint. The hip joint is a ball-and-socket joint. The “ball” is the head of the femur and the “socket” is the cup-shaped acetabulum.
The joint surface is covered by a smooth articular surface that allows pain-free movement of the joint.
The cartilage cushions the joint and allows the bones to move on each other with smooth movements.