The |pelvis| creates the basin of the lower abdominal cavity. It is formed by three separate bones which become fused: the |ilium|, the |ischium|, and the |pubis|. The |ilium| is the broad, wing-like segment which features the wide, slightly concave surfaces of the back and sides of the pelvic girdle. The |ischium| forms the smaller, lower, portion which bears the weight of the body while sitting. The |pubis| creates an archway in the front of the basin which allows the |urethra|, ~blood~ vessels, and ~nerves~ to pass through the pelvic girdle to the external genitalia and lower body. The |pelvis| articulates with the |sacrum| in the back (and thereby connects to the rest of the |vertebral column|) and to the legs through the ball-and-socket joint formed by the two acetabula of the |pelvis| and the head of each |femur|.