The medial calcaneal nerve: anatomy and nerve conduction technique.

We report a new technique for studying conduction in the medial calcaneal nerve (MCN). Dissection of 14 cadaver feet revealed the optimal G1 site to be one third of the way from the apex of the heel to a point midway between the navicular tuberosity and the prominence of the medial malleolus. Seventy-two feet (36 healthy volunteers) were studied using surface stimulation of the tibial nerve 10 cm proximal to the G1 surface electrode. Averaging technique was not required. Reference values (mean +/- 2 SD) were determined for MCN onset latency (2.0 +/- 0.3 ms), peak latency (2.5 +/- 0.3 ms), onset conduction velocity (61 +/- 11 m/s), peak conduction velocity (40 +/- 5 m/s), baseline-to-peak amplitude (18 +/- 6 microV), and maximum intrasubject side-to-side differences in these values (0.3 ms, 0.3 ms, 15 m/s, 5 m/s, and 17 microV, respectively). This study provides an easily performed, reproducible method for electrophysiologic evaluation of the MCN.