Overview
The quadratus lumborum, often shortened to QL, is a deep rectangular muscle on each side of the lower back. It spans the space between the top of the pelvis and the lowest rib, with attachments to the lumbar vertebrae.
Location and Connections
- Begins along the iliac crest and iliolumbar ligament
- Attaches to the twelfth rib and lumbar transverse processes
- Lies beside the psoas and in front of the erector spinae
- Forms part of the posterior abdominal wall
What It Does
One QL helps side-bend the trunk toward the same side. Together, the pair assists trunk extension and helps stabilize the lowest rib during breathing. It also contributes to controlling the pelvis during walking and carrying.
Common Problems
The QL can become sore after lifting, carrying on one side or unfamiliar activity. Pain in its area can also come from other muscles, the lumbar joints, ribs, hips or nerves, so location alone is not a diagnosis.
Clinical Relevance
Rehabilitation may include comfortable trunk motion followed by progressive carrying, hip and trunk strengthening. Forceful stretching is not automatically the answer; the useful dose depends on what movements are limited or sensitive.
Related Anatomy
References
- StatPearls. "Anatomy, Abdomen and Pelvis, Quadratus Lumborum." https://www.ncbi.nlm.nih.gov/books/NBK537212/
- StatPearls. "Anatomy, Abdomen and Pelvis, Posterior Abdominal Wall." https://www.ncbi.nlm.nih.gov/books/NBK557605/