Chorda tympani nerve fibers in man.

Four normal human chorda tympani nerves were studied for quantitative data of nerve fibers. The average total number of nerve fibers was 5360 (range, 4941-6020). The average number of unmyelinated fibers was 1835 (range, 1518-2083), or 34% of the total. The diameters of myelinated fibers ranged from 1 to 7 microns, peaking at 2 microns. Most of the unmyelinated axons had a diameter between 0.5 and 2 microns. The importance of the quantitative evaluation of the chorda tympani nerve fibers is stressed in reporting structural changes.