[Methodology and normal values for the recording of evoked muscle potentials following stimulation over motor roots].

In 28 healthy subjects the peripheral nervous system was stimulated with brief high-voltage condenser discharges over the vertebral column. Latencies were correlated with the length of the extremity. The following normative data were obtained: M. biceps brachii 5.2 ms (SD 0.37 ms), M. abductor pollicis 14.2 ms (SD 0.86 ms), M. tibialis anterior 16.2 ms (SD 1.0 ms), M. extensor digitorum brevis 25.0 (SD 1.3 ms). Comparison of these latencies with those obtained by F-wave studies support the idea that motor roots are stimulated by this method.