Experimental studies on the dorsal nerve of the penis of the rat

Dorsal nerves of the rat penis were studied in osmium tetroxide‐treated sections for number and diameter distribution of myelinated fibers. The mean count in four nerves was 1423 fibers. The percentage distribution of diameters was unimodal with the peak at 5‐6 μ. Counts taken at different levels of the nerve showed a proximo‐distal decrease in the number of fibers but no difference in the percentage a distribution of fiber diameters. The compound action potential of the dorsal nerve exhibited potential waves with conduction velocities between 62 and 10 meters/second, which correlates well with the histological data. Counts of myelinated fibers in the dorsal nerve of four animals 14, 26, 38 and 70 days after section of the ipsilateral pudendal nerve revealed complete degeneration at 14 days, progressive regeneration at 26 and 38 days, and complete recovery at 70 days. The percentage distribution of diameters in the nerves at different stages of regeneration was essentially the same. The rate of regeneration expressed as percentage of the total number of fibers from day 14 to day 36 was approximately 1.2% day and from day 36 to day 70 approximately 2.2% /day.