This is the upward arched superior border of the ilium separating the internal and external surfaces. The arch is not in a single plane, but follows a gradual sinuous curve. It ends anteriorly and posteriorly as the blunt anterior and posterior superior spines of the ilium. The highest point on the crest is level with a plane between the third and fourth lumbar spines. The crest can be divided into an internal lip, an intermediate region, and an external lip. These surfaces provide attachment for the lateral abdominal wall muscles, the quadratus lumborum, the latissimus dorsi, the iliocostalis, the gluteus maximus, and the tensor fasciae latae.

A crest refers to a ridge-like projection. The Latin equivalent of the term is crista.

Crista

Crête