Acetabular

Acetabular is a medical term relating to the acetabulum, the cup-shaped socket of the hip joint in the pelvis. The acetabulum articulates with the femoral head to form the hip joint, enabling a wide range of lower-limb movements. It is part of the innominate bone (os coxae) and is formed by the fusion of three bones: the ilium, ischium, and pubis.

Anatomically, the acetabulum consists of an articular surface and a non-articular region. The lunate surface is the horseshoe-shaped portion covered by hyaline cartilage that contacts the femoral head, while the acetabular fossa is the non-articular, fat-filled internal part. The acetabular rim is reinforced by the acetabular labrum, a fibrocartilaginous ring that deepens the socket and helps seal the joint. The inferior rim features the acetabular notch, bridged by the transverse acetabular ligament to form a foramen.

Clinical relevance includes acetabular fractures, which are classified by patterns involving the walls and weight-bearing dome and are evaluated using established schemes. The acetabulum can also be involved in dysplasia, osteoarthritis, and impingement syndromes. In hip replacement surgery, an acetabular cup is implanted into the socket portion of the joint. Knowledge of acetabular anatomy and variants is important for diagnosis, planning, and surgical approaches, including considerations of orientation and stability in arthroplasty and fracture management.