Intratrunk Structure and Myeloarchitectonics of The Facial Nerve at The Level of The Stylomastoid Foramen in Adults

Abstract

The aim of the presented study was to study the intratrunk structure of the facial nerve at the exit from the stylomastoid foramen. Material and methods. Fragments of the nerve were taken to study the intratrunk structure of the facial nerve at the exit from the stylomastoid foramen of the facial nerve. During microscopic examination, special attention was paid to the study of the features of the internal structure of the facial nerve - the shape, number, size and topography of nerve fibers. The quantitative indicators obtained during the study were carried out in the IBM Statistics SPSS-26 program using the variational and dispersion methods. To describe the variation series in the analysis of indicators, the following were calculated: mean (M), standard error (±m), 95% confidence interval (95% CI) and the average structure - Me (median), the smallest and largest (min, max) indicators. The results of the study showed that the myelinated fibers of the stem part of the facial nerve, emerging from the stylomastoid foramen, consist of conductive elements that have undergone myelination and differentiation in the nerve. As part of the facial nerve, small nerve bundles were identified, consisting of only a few myelinated nerve fibers, usually occupying the peripheral parts of the nerve trunk. It should be noted that, in general, the number of myelinated nerve fibers in the facial nerve does not change significantly in adulthood. Conclusion. In adulthood, the myeloarchitectonics of the facial nerve is characterized by distinct polymorphism, the presence of all types of myelin fibers in each nerve bundle. There are different, individual and age-related variability of the main indicators of myelinated nerve fibers, which is associated with certain individual dynamics and age-related restructuring of the connective tissue sheath.