Iliolumbar ligament

The iliolumbar ligament is attached above to the lower and front part of the transverse process of the fifth lumbar vertebra.

It radiates as it passes lateralward and is attached by two main bands to the pelvis.

The lower bands run to the base of the sacrum, blending with the anterior sacroiliac ligament; the upper is attached to the crest of the ilium immediately in front of the sacroiliac articulation, and is continuous above with the lumbodorsal fascia.

In front, it is in relation with the Psoas major; behind, with the muscles occupying the vertebral groove; above, with the Quadratus lumborum.