Quadratus Lumborum
Musculus quadratus lumborum
The quadratus lumborum is a deep, quadrilateral muscle of the posterior abdominal wall that connects the pelvis, 12th rib, and lumbar spine. It produces lateral flexion and, bilaterally, lumbar extension, while also hiking the hip and stabilizing the lower back and 12th rib. It is a major frontal-plane core stabilizer in suitcase carries, single-leg work, and offset loading, and is a common source of low-back tightness.
- Actions
- Lateral flexion of the lumbar spine (unilateral), Extension of the lumbar spine (bilateral), Hip hiking / pelvic elevation, Stabilizes the 12th rib during respiration
- Origin
- Iliac crest and iliolumbar ligament
- Insertion
- 12th rib and transverse processes of lumbar vertebrae L1-L4
- Innervation
- Anterior rami of T12 (subcostal nerve) and L1-L4
- Blood supply
- Lumbar arteries, lumbar branch of iliolumbar artery, subcostal artery
Antagonists Rectus Abdominis
Tendons Thoracolumbar Fascia
Exercises (14)
Trains as a primary mover
Assists in