The quadratus lumborum or QL is a common cause of back pain which is to one side and comes on after lifting or twisting.
- Posterior iliac crest.
- Iliolumbar ligament.
- Twelfth rib.
- Transerve processes of L1-L4.
- Lateral flexion (side-bends) of the trunk.
- Ventral rami of the subcostal nerve.
- Lumbar nerves.
- Bending sideways to pick something up.