Degree of Myelination (g-ratio) of the Human Hypoglossal Nerve

Abstract

Introduction The degree of myelination (g-ratio) can be useful to the evaluation of the fiber morphology during peripheral nerve regeneration and in studies in the area of microsurgery. Therefore, the aim of this analyze was to investigate the g-ratio of the human hypoglossal nerve.

Materials and Methods The hypoglossal nerve was bilaterally analyzed in human specimens obtained from necropsies (6 subjects). The nerves were analyzed using histology, and the morphometric parameters (axon diameter and myelinated fiber diameter) were measured using Image Pro-Plus Software 6.0.

Results Quantitative comparison of the g-ratio demonstrated no statistically significant difference between the left and right human hypoglossal nerves. In addition, the values of the g-ratio of both hypoglossal nerves were considerably higher than the normal values for the peripheral nerve fibers. This demonstrates a low degree of myelination of the hypoglossal nerve, bilaterally.

Conclusion Knowledge of the variations of the human hypoglossal nerve, are clinically important especially in the area of microsurgery (techniques used for reinnervation).

Keywords

hypoglossal nerve - g-ratio - axon diameter - myelinated fiber diameter - human

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