Nerve Diameter in the Hand: A Cadaveric Study.

Background: Nerve injuries in the hand are common and often pose a challenge for the upper extremity surgeon. A range of reconstructive options exist for nerve repair, but proper matching of nerve diameter is important for many of these techniques. The purposes of this study were to (1) describe the nerve diameters of the hand and their relative differences and (2) investigate whether there is a relationship between nerve diameter and external hand dimensions or body mass index.

Methods: We utilized 18 freshly frozen cadaveric hands from adult donors aged 20-86 of both sexes for this study. Two independent observers measured each nerve diameter to the nearest 0.1 mm using a digital caliper.

Results: Using the flexor zones as boundaries, a total of 33 nerve measurements were performed for each cadaveric hand. Nerve diameter increased from the distal to the proximal flexor zones. The internal common digital nerves in flexor zone 3 were larger than the external digital nerves. The median nerve was found to be nearly 2 times larger than the ulnar nerve at 2 locations within the wrist. There was a positive correlation between body mass index, hand span, hand width, and nerve diameter at several measured locations.

Conclusions: This study provides reference values for nerve diameters of the hand and wrist and describes their relative differences. It is important for surgeons to be aware of these differences and to consider this information as we advance our efforts to reconstruct the hand and develop technologies for nerve repair.