[Section of the median nerve at the wrist].

Introduction: The usefulness of neurophysiological studies of peripheral nerves depends basically on an understanding of the physiopathology, especially of the evolutionary aspects of the phenomena of reinnervation.

Clinical Case: We present the case of a girl with complete section and immediate anastomosis of the two cut ends of the median nerve, at the wrist. Sixty two days later she had unmistakable signs of reinnervation (response in the thenar eminence to an electrical stimulus of 300 uV in amplitude and 42 ms in latency, with denervation and reinnervation on the EMG of the abductor pollicis brevis muscle).

Discussion: The findings in our patient show a rather faster rate of nerve regeneration than is usually accepted in the literature. This may have been due to suitable selection of some of the parameters of the neurophysiological study, such as time of analysis and sensitivity, which when not satisfactory may lead to an impression of failure or delay in reinnervation.