The acetabulum is formed by contributions of which bones?

• A. Ilium, Ischium, Pubis
• B. Femur
• C. Tibia
• D. Pelvis

Answer: (A)

The acetabulum is the hip socket formed by three bones that make up each half of the pelvis: the ilium, ischium, and pubis. Each contributes a portion of the socket—ilium provides the superior rim, pubis the anterior part, and ischium the posterior-inferior portion—so the head of the femur can articulate securely. In development these bones join at the triradiate cartilage and, as you mature, fuse to form a single acetabular socket. The femur forms the joint with this socket, but is not part of its formation, and the tibia is a separate bone of the leg, not involved in constructing the acetabulum.