The quadratus lumborum is a flat sheet of deep muscle fibers located on each side of the spinal column.

Origin

The quadratus lumborum originates on the crest of the ilium and the ligament and transverse processes of the lower four lumbar vertebrae.

Insertion

Insertion is on the transverse processes of the upper two lumbar vertebrae and the lower border of the last rib.

Function

Pulls the trunk backward and to the side.

Side Bend