Location of nerve entry points of flexor digitorum profundus

The aim of this study was to elucidate the anatomical location of nerve entry points of Flexor digitorum profundus (FDP) and its implications for non-surgical neurolysis. A total of 21 amputated forearms of 11 Korean fresh cadavers were dissected. Two transverse x-axes joined the medial and lateral epicondyles and the radial and ulnar styloid processes. The longitudinal y-axis joined the midpoints of the proximal and distal transverse x-axes. The locations of the points were marked relative to the forearm length (x) and forearm width (y). The number of nerve entry points from median nerve and ulnar nerve were average 3.91 +/- 0.62 (range 3-5, median 4) and 2.14 +/- 0.65 (range 1-3, median 2) respectively. Most (82.9%) nerve entry points of FDP from the median nerve were within two circles, with 15 mm diameter. The two circles were on medial 1/10 of forearm width from the y-axis, and on proximal 1/3 (1:2) and 2/5 (2:3) of forearm length on x-axis. Most (80.0%) nerve entry points of the ulnar nerve innervating FDP were within a 15 x 30 mm rectangle. Its center was located at +26.5% on x-axis and -36.0% on y-axis. The nerve entry points used to be selected in performing nonsurgical neurolysis with either ethyl alcohol (50%) or phenol (5-12%).