The hip bone is composed of three elements:
which fuse at the acetabulum (the socket of the hip joint).
The ilium is the wide blade-like upper part of the hip bone. It has a prominent ridge running along its upper surface (the iliac crest) for the attachment of body wall muscles. Its outer surface form the origin of the 3 gluteal muscles (gl. maximus, medius and minimus) and bears ridges (gluteal lines) which separate their attachments.
The ilium has four protuberances:
The anterior superior iliac spine is an attachment site for the inguinal ligament and the sartorius muscle. The anterior inferior iliac spine is an attachment site for the capsule of the hip joint, especially the iliofemoral ligament.
The iliac crest is an important landmark for surface anatomy. The crest delineates the abdomen from the gluteal region.
NB. ili(o)- is a prefix denoting the ilium
cf ile(o)- is a pefix denoting the ileum (The ilium being the lowest part
of the small intestine)