What is Hip bone?

The hip bone is a large irregular bone, constricted in the center and expanded above and below. In some vertebrates it is composed of three parts: the ilium, ischium, and the pubis.

The two hip bones join at the pubic symphysis and together with the sacrum and coccyx comprise the skeletal component of the pelvis – the pelvic girdle which surrounds the pelvic cavity. They are connected to the sacrum, which is part of the axial skeleton, at the sacroiliac joint. Each hip bone is connected to the corresponding femur through the large ball and socket joint of the hip.