The detailed anatomy of the palmar cutaneous nerves and its clinical implications.

The forearms and hands of 40 fresh-frozen cadavers were dissected under the microscope to study the palmar cutaneous branch of the median nerve (PCBm) and the palmar cutaneous branch of the ulnar nerve (PCBu). Branches of the PCBm innervating the scaphoid were typically found, but in no specimen did we find a 'typical' cutaneous branch of the ulnar nerve. According to our findings, standard incisions for open carpal tunnel release carry a significant risk of damaging branches of the PCBm or PCBu. The chance of injury to these sensory nerves can be minimized by using a short incision in the proximal palm or a twin incision approach, which we describe. Because the PCBm is closely associated with the ulnar side of the flexor carpi radialis (FCR) sheath, this sheath should be opened on the radial side during harvest of the FCR tendon for transfer. When transferring the palmaris longus tendon, it should be cut proximal to the distal wrist crease to avoid possible damage to the PCBm.