Illustration of an arthritic hip joint (Articulatio coxae), pelvis and lumbar vertebrae. The hip joint is made of the femur head and the acetabulum that is partially removed here. It enables flexion, extension, abduction, adduction and spinning. Arthrosis describes an irreversible damage of the joint that often caused by mistress. It can be caused by accident or hereditary cartilage defects, too. Arthrosis begins with decay of the articular cartilage, reconstructive processes in adjacent pones with decay of articular surfaces follows. This causes pain, rigidity of the joint, and progressing malformations. In the final stage, the joint can totally ossify.