Object: The isolated posterior femoral cutaneous nerve (PFCN) neuropathy has rarely been described in the literature and documented electrophysiologically, based on the paucity of published report. The purpose of this study was to assess the reference value of somatosensory evoked potentials (SSEP) in posterior femoral cutaneous nerve.

Method
Both legs of twenty healthy adults were tested. Somatosensory evoked potentials were obtained with the active recording electrode placed at Cz', 2 cm posterior to C_Z, and the reference electrode at F_Z (international 10∼20 system). The posterior femoral cutaneous nerve was excited 14 cm proximal to the midpopliteal fossa between the long head of the biceps femoris and the semitendinosus muscles.

Results
The mean latency of right P1 were 35.35⁑3.17 msec, N1 were 45.28⁑2.71 msec and mean peak amplitudes were 1.42⁑0.98 μV. In the left side, mean latency of P1 were 34.54⁑2.89 msec, N1 were 43.87⁑2.44 msec and mean peak amplitudes were 1.20⁑0.53 μV.

Conclusion
Based on the result of this study, the reference values could be used to differentiate and detect the lesion in the case of isolated dysfunction of the posterior femoral cutaneous nerve.