Axilla to elbow radial nerve conduction

Numerous techniques that evaluate radial nerve conduction from the axilla or supraclavicular fossa to the elbow have been reported. A shortcoming of most protocols is determining the precise radial nerve length as it proceeds along the spiral groove. The present study dissected out and measured directly eight cadaver radial nerves from the axilla to the elbow. These values were compared with a new surface tape measurement technique from axilla to elbow across the bicep muscle, obstetrical calipers over this region, and a surface determination approximating the course of the radial nerve posteriorly in the spiral groove. The anterior surface tape-measuring procedure compared most favorably with the actual anatomic length. Nerve conduction velocities were then calculated in 20 volunteers using all 3 techniques and compared with the median nerve in the arm. The anterior and posterior tape measurements yielded a conduction velocity of 72.5 +/- 4.7 and 86.6 +/- 7.0 m/s, respectively, whereas the caliper resulted in 65.7 +/- 3.9 m/s. We conclude that proximal radial nerve length assessment employing an anterior tape measurement from axilla to elbow across the bicep musculature is precise and compares favorably with the actual anatomic length of the radial nerve.