The hip bone, innominate bone or coxal bone's a large, flattened, irregularly shaped bone, constricted in the center and expanded above and below. It's one of the few ball and socket synovial joints in the body – the so called hip joint. It meets its fellow on the opposite side in the middle line in front, and together they form the sides and anterior wall of the pelvic cavity. Together with the sacrum and coccyx, it comprises the pelvis. Components It consists of three parts, the ilium… (More on Hipbone)