Morphometric Analysis of Diameter and Density of Myelinated and Unmyelinated Fibers of Normal Human Sural Nerves

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) × 10³ (mean ± standard deviation) per square millimeter. The border diameter between small and large myelinated fibers was 5.4 ± 0.5 μm. The densities of small and large myelinated fibers in cross sectional areas were (4.5±0.9)×10³ and (2.9 ± 0.7) × 10³ per square millimeter, respectively. The density of unmyelinated fibers was (27.9±5.8)×10³ 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±0.12μm, 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.