Hip Bone

The hip bone, innominate bone, pelvic bone or coxal bone is a large, flattened, irregularly shaped bone, constricted in the center and expanded above and below. In some vertebrates (including humans) it it composed of three bones; ilium, ischium, and pubis.

The two hip bones joins at the pubic symphysis and together with the sacrum and coccyx, the hip bone comprises the skeletal component of the pelvis, the pelvic girdle, which surrounds the pelvic cavity. The hip bone forms the primary connection between the bones of the lower limb and the axial skeleton at the sacroiliac joint. The hip bone also contains a large ball and socket joint, the hip joint, which connects the femur to the pelvis.