Medial femoral cutaneous nerve conduction study with distal recording: A novel technique.

Abstract

A new technique to obtain the sensory nerve action potential (SNAP) of the medial femoral cutaneous nerve is described. SNAPs were recorded from 104 subjects with a bar recording electrode 10 cm proximal to the patella along an imaginary line drawn between the medial edge of the patella and the femoral pulse below the inguinal ligament. Stimulation was applied 14 cm proximal to the recording point. There were 104 healthy subjects. Onset latency of the SNAPs was 2.20 ± 0.16 ms (mean ± SD), peak latency was 2.70 ± 0.16 ms, peak-to-peak amplitude was 7.5 ± 3.0 μV, and conduction velocity was 51.5 ± 3.0 m/s. The side-to-side difference in the mean amplitude was 22.27 ± 13.6%. This new technique is easy, reliable, and reproducible, and should prove useful for the evaluation of neuropathies of the medial femoral cutaneous nerve.