Anatomy of the hip - Dr. Michael Lehmann
The structure of the hip joint
After the knee, the hip joint (Articulatio coxae) is the second-largest joint in the human body and therefore has an important role to play in the context of hip joint diseases. It is referred to as a ball-and-socket joint. Ball-and-socket joints have the advantage that they allow three-dimensional movements, which is partly why the hip joint is so mobile. Bending, stretching, spreading, internal and external rotation.
Amongst the most important structures of the hip joint are the femoral head (Caput femoris), which is around five centimetres thick, for example, and the hip joint socket (acetabulum) in the pelvis.
To cause as little friction as possible between these two joint partners, both the head and the acetabulum are lined with a smooth layer of cartilage that is just a few millimetres thick.
The edge of the acetabulum is surrounded by a lip of cartilage (Labrum acetabuli) which acts like a sealing ring and closes the joint line off from the outside.