ELECTROMYOGRAPHIC STUDIES ON CATS AFTER SECTION AND SUTURE OF THE SCIATIC NERVE

Abstract

An investigation was made concerning the time course of electrical activity in the tibialis anticus muscles of 6 cats after section and immediate suture of their nerve supply. Fibrillation voltages were recorded throughout the lengths of all muscles for various time intervals following denervation. There was a definite but unmeasurable decrease in the number and frequency of fibrillation voltages prior to beginning motor-unit recovery. There was a decrease in the total number of areas showing continuous fibrillation, but there was no cessation of continuous fibrillation in all areas of any one muscle prior to beginning motor-unit recovery. Electrical silence did not bear a close correlation with either severe morphologic changes in muscle or beginning motor-unit recovery. The motor-unit voltages associated with beginning motor-unit recovery were of poly-phasic wave form in all instances. The avg. duration of the motor-unit-spread interval was 11.66 days. Beginning motor-unit recovery preceded unequivocal functional recovery in all instances. Motor-unit voltages were elicted from all 4 areas in 5 muscles and from 2 areas in the 6th when the muscle showed unequivocal functional" recovery. The avg. duration of the functional delay interval was 12 days. Complete functional recovery preceded complete electromyographic recovery in all instances. The avg. rate of reinnerva-tion (using beginning motor-unit recovery as a sign of rein-nervation) was 2.61 mm./day. Complete functional recovery occurred in all muscles even though they were proved by electromyography to be fibrillating for various time intervals after denervation.