It is bounded by a prominent uneven rim, thick and strong on top, which serves as the point of attachment for the acetabular labrum.

[4] The acetabulum is also home to the acetabular fossa, an attachment site for the ligamentum teres, a triangular, somewhat flattened band implanted by its apex into the antero-superior part of the fovea capitis femoris.

[2] The well-fitting surfaces of the femoral head and acetabulum, which face each other, are lined with a layer of slippery tissue called articular cartilage, which is lubricated by a thin film of synovial fluid.

The perforate acetabulum is a cup-shaped opening on each side of the pelvic girdle formed where the ischium, ilium, and pubis all meet, and into which the head of the femur inserts.

[8][9] The orientation and position of the acetabulum is one of the main morphological traits that caused dinosaurs to walk in an upright posture with their legs directly underneath their bodies.

In a relatively small number of dinosaurs, particularly ankylosaurians (e.g. Texasetes pleurohalio), an imperforate acetabulum is present, which is not an opening, but instead resembles a shallow concave depression on each side of the pelvic girdle.