Morphometric analysis of diameter and density of myelinated and unmyelinated fibers of normal human sural nerves

Abstract

Diameter and density of both myelinated and unmyelinated fibers were morphometrically analyzed in 8 sural nerves obtained from 8 normal volunteers by utilizing a TGA-10 particle analyzer (Carl Zeiss Co., West Germany). The density of total myelinated fibers was (7.4 +/- 1.3) X 10(3) (mean +/- standard deviation) per square millimeter. The border diameter between small and large myelinated fibers was 5.4 +/- 0.5 micron. The densities of small and large myelinated fibers in cross sectional areas were (4.5 +/- 0.9) X 10(3) and (2.9 +/- 0.7) X 10(3) per square millimeter, respectively. The density of unmyelinated fibers was (27.9 +/- 5.8) X 10(3) per square millimeter. The peak and the median diameters in the size distribution of unmyelinated fiber diameters were 0.88 +/- 0.15 and 0.86 +/- 0.12 micron, respectively. The mean distribution histograms of the sizes of both myelinated and unmyelinated fibers of 8 sural nerves were also established. The morphometric findings obtained in this study serve as control in histopathologic analysis of the sural nerves from the patients with various peripheral neuropathies.