Nerves in quadratus lumborum planes: A cadaveric study.

Dermatomal analgesia achieved with quadratus lumborum blocks is site-dependent and inconsistent. Cadaveric and clinical studies reveal multiple mechanisms of action. We dissected six fresh human cadavers bilaterally and thoroughly studied their neurological linkages to the quadratus lumborum muscle (QLM) to identify neural structures and block targets. At the end of the investigation, only the subcostal nerve (anterolateral) and the ilioinguinal nerves were found near the QLM in all specimens. The iliohypogastric nerve was found in only two specimens. No further neural targets were found in the fascial planes before and posterior to the QLM.