ilium /il″ē·əm/ pl. ilia [L, flank] , the uppermost of the three bones that make up the innominate bone (hip bone). The ilium forms the superior part of the acetabulum and provides attachment for several muscles, including the obturator internus, the gluteals, the iliacus, and the sartorius. Compare ischium, pubis. −iliac, adj.
