The quadratus lumborum is a muscle in the posterior inferior trunk lateral to the spine (see Image. Abdominopelvic Muscles). This muscle attaches to the iliac crest, the transverse processes of lumbar vertebrae 1 to 4, and the 12th rib. The quadratus lumborum's complex organization makes it difficult to precisely identify its actions through the contraction of its fibers. This muscle is an integral part of the thoracolumbar fascia.
Uncertainty persists about whether a quadratus lumborum abnormality is the primary source of back pain. This muscle potentially acts as a junction of the forces exerted by the neighboring muscles, influencing the vectors of the different tensions produced. The quadratus lumborum is a significant means of access for anesthesia during surgery on the back, lower limbs, or abdominal area, thanks to its strategic position and the entropic scheme of its fibers. Understanding the latest anatomical and clinical information on the quadratus lumborum is essential for treating various musculoskeletal conditions of the lower back.
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