MORPHOLOGICAL AND MORPHOMETRIC ANALYSIS OF FASCICULAR STRUCTURE OF TIBIAL AND COMMON PERONEAL NERVES

Abstract

In clinical practice, the common peroneal nerve palsy is more frequent compared to the tibial nerve, although both are part of the sciatic nerve. The aim of our study was to analyze and compare the fascicular structure of the tibial and common peroneal nerve. For the study we used tissue samples of the sciatic nerve, 19 subjects aged 8–86 years. The samples were processed by standard histological procedures, after which were made transverse sections of 5 microns and stained with hematoxylin-eosin staining. First, we analyzed the number, size and arrangement of fascicle. After that we made photographs of each common peroneal and tibial nerve fascicules and to each the area and maximum diameter were determined. In all studied cases, a connective tissue septum that separates the fascicular groups, tibial and common peroneal nerve was detected. The tibial nerve fascicular group was numerous and medially localized while the common peroneal nerve fascicular group was less numerous and placed laterally. Morphometric analysis showed that the common peroneal nerve has statistically significantly lower number of fascicles (16.28 ± 4.39) and the total fascicular area (2.13 × 106 ± 8.91 × 106 μm2) compared to the tibial nerve (average 35 fascicles ± 13.29 and mean fascicular area 5.05 × 106 ± 2.46 × 106 μm2). The average value of the maximum diameter and the average area of the investigated fascicle, tibial and common peroneal nerves showed no statistically significant differences. Correlation analysis of the studied parameters with the age of subjects also did not reach statistical significance. Fascicular structure with a smaller number of larger fascicles and sparse epineurial connective tissue sheath may increase susceptibility of the common peroneal nerve injury.