Does a Real Henle's Nerve Exist? A Detailed Anatomic Study

The purpose of this study was to delineate the detailed distribution of the palmar cutanaeous nerve and its branches in the hand.

Forty fresh-frozen cadaver forearms and hands were dissected (30 cadavers, 23 male hands, 17 female hands). Three standard incisions were used for the exposure: a longitudinal incision through the center of the forearm and hand, two transverse incisions over the distal wrist crease and distal palmar crease. Full-thickness skin flaps were elevated and every branch of the ulnar nerve from the forearm or hand was carefully identified, dissected, and followed under 3.5 loupe magnification. The dissection of the palm was done using a surgical microscope with X10 magnification.

A typical single trunk of the PCBU (palmar cutaneous branch of the ulnar nerve) arising directly from the ulnar nerve itself and terminating in the palmar skin, was not found in any specimen. Any branch from the ulnar nerve to the ulnar neurovascular bundle in the distal forearm (so-called nerve[s] of Henle) was not considered to be a true palmar cutaneous nerve. Instead of one clearly defined trunk, several palmar cutaneous branches were found. All these branches originated from the ulnar digital nerve to the little finger. On average, there were four branches (range: 3–10) with a mean length of 9 mm (range: 4–17 mm). The most proximal branch arose 3 mm distal to the wrist crease. In all specimens, the skin at the ulnar side of the palm was innervated by these cutaneous branches.

No single trunk (PCBU) was found in this study, confirming the fact that a true PCBU is most uncommon. The innervation of the ulnar side of the palm appeared to stem exclusively from multiple branches of the ulnar digital nerve to the small finger. An incision line on the ulnar aspect of the ring finger for carpal tunnel release can minimize the chance of cutting palmar branches of the median nerve, but can significantly increase the risk of damaging the PCBU branches.