The |ischium| is one of the three sections of bone which are fused in the adult to form the |pelvis|. The |ischium| bears the weight when sitting, and is attached to the |pubis| in front and to the |ala|, or wings, of the ilium laterally and to the back. The large openings in the |ischium| on either side of the |pelvis|, just below the |pubis|, are called the obturator foramina.