Iliac crest

The crest of the ilium (or iliac crest) is convex in its general outline but is sinuously curved, being concave inward in front, concave outward behind.

Anatomy
It is thinner at the center than at the extremities, and ends in the anterior and posterior superior iliac spines.

The surface of the crest is broad, and divided into external and internal lips, and an intermediate line.

About 5 cm behind the anterior superior iliac spine there is a prominent tubercle on the outer lip.

To the external lip are attached the Tensor fasciæ latæ, Obliquus externus abdominis, and Latissimus dorsi, and along its whole length the fascia lata; to the intermediate line the Obliquus internus abdominis.

To the internal lip, the fascia iliaca, the Transversus abdominis, Quadratus lumborum, Sacrospinalis, and Iliacus.

Clinical significance
The iliac crest has a large amount of red bone marrow, and thus it is the site of bone marrow harvests (from both sides) to collect the stem cells used in bone marrow transplantation.