Bone · Pelvis

Ilium

Os ilium

The ilium is the large fan-shaped upper part of the hip bone — the blade you rest your hands on at your waist. It is a hand-off point between the trunk and the leg. Its rim and its front and back corners anchor the abdominal wall and the low-back fascia from above, and the gluteal muscles and tensor fasciae latae take origin from its outer surface and run down to the thigh. Its inner surface holds the iliacus, one half of the deep hip flexor. It joins the sacrum behind at the sacroiliac joint, and its lower part builds the upper wall of the hip socket.