The quadratus lumborum is a deep muscle of the abdomen. It originates from the crest of the ilium and the transverse processses of the lower lumbarvertebrae and extends to the last rib. Four small tendons also extend to the transverse processes of the upper lumbarvertebrae. The quadratus lumborum is innervated by the upper lumbar nerves and supplied by the lumbar arteries. This muscle assists in breathing by pulling down the last rib and helps flex the trunk. Research Quadratus Lumborum
 
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