What muscle originates from the iliolumbar ligament?

The quadratus lumborum muscle is the one that originates from the iliolumbar ligament, a structure that connects the iliac crest to the lumbar vertebrae. This ligament serves as an attachment point, providing stability to the lumbar spine and pelvis. The quadratus lumborum plays a significant role in lateral flexion of the trunk and also aids in stabilizing the pelvis during movements. Its position and origin from the iliolumbar ligament make it integral to maintaining postural alignment and supporting movements involving the lower back.

The other muscles listed do not have this specific origin. Interspinalis muscles, for example, are small muscles that run between adjacent vertebrae, primarily involved in extension and stabilization of the spine. Rotatores are situated between the vertebrae and assist in spinal rotation, while multifidus spans several vertebrae and contributes to spinal stability, but none originate from the iliolumbar ligament. This specificity highlights why the quadratus lumborum is the correct choice.