Cutaneous distribution of the ulnar nerve in the palm: does it cross the incision used in carpal tunnel release?

An anatomical study was performed on the ulnar nerve to determine whether branches are present in the region of the incision for open or endoscopic carpal tunnel release that may be transected or traumatized, resulting in painful neuromata or dysesthetic symptoms. Twenty-four cadaveric forearms were dissected under 3.5-loupe magnification. A palmar cutaneous branch of the ulnar nerve was found in 42% of the limbs. Branches of the nerve were found in the proximity of the incision for carpal tunnel release in 12.5%. The palmar cutaneous branch of the median nerve was present in 92% of the limbs, with 8% having a branch in proximity to the incision. These anatomical findings suggest that injury to the palmar cutaneous branch of the ulnar nerve may be responsible for the "painful scar" more often than the palmar cutaneous branch of the median nerve.