Ilium

Os ilium

SkeletalSkeletonPelvisLeft and right

View left in 3D View right in 3D

What it is

The large fan-shaped upper part of the hip bone: a thin wing (ala) with the concave iliac fossa inside, bounded above by the iliac crest from the anterior superior iliac spine (ASIS) to the posterior superior iliac spine (PSIS).

Function

Supports the abdominal organs, anchors the abdominal, gluteal and iliacus muscles, and joins the sacrum at the sacroiliac joint.

Size

Crest ≈ 25 cm long; ASIS to PSIS ≈ 16 cm

Clinical note

The iliac crest is a standard donor site for bone grafts and marrow biopsy; the ASIS is a key surface landmark.