Macro-Microscopic Features of the Leg Muscles Innervation

Abstract

The purpose of the study was to disclose topographic anatomical features of the extra- and intramuscular innervation points of the leg. Materials and methods. 15 adult human subjects and one-month old baby legs at three levels were studied using such methods: cross-sections according to N.I. Pirogov technique, histotopographic sections, macro-microscopic method, histological staining with hematoxylin-eosin and Krutsay. Results. In our macro-microscopic study, the main attention was paid to the individual anatomical variability in the innervation of the lower leg muscles. Study of the nerves of the leg muscles allowed to clarify the course of the neurovascular bundle of the leg at its three levels, taking into account individual age characteristics, and also to show the myeloarchitectonics of both the main nerve trunks and their intramuscular branches. Such differences in the location of the leg muscles of an adult and of one month-old baby undoubtedly related to the fact that the child’s muscular belly is longer in relation to the tendon. The histotopography of intramuscular nerves on total transverse sections of antagonistic muscles was studied: flexor and extensor digitorum longus, longus flexor and extensor of the big toe, and also the spectrum of myelin fibers contained in these nerves in a one-month-old baby and an adult was investigated. On histotopographic sections of the extensor digitorum longus nerve in a one-month-old baby, thick-diameter myelin fibers are absent, whereas in the long finger flexor nerve, on average, they are 0.5%. The number of thin and medium is respectively 8%, 13% and 83.5%, 16%. However, we have determined individual anatomical variability in the location of the vessels in relation to the main nerve trunks, as well as differences in the topography of the nerve in the corresponding muscles. Conclusion. In the nerves of the leg muscles, features were found, both in quantitative and qualitative composition of the conductors forming them; in the nerves of the flexor muscles, the composition of the nerve fibers is more diverse (with a slight predominance of the number of medium, thick and very thick fibers), which is associated with the peculiarity of their functions; in adulthood, the % ratio in the spectrum of myelin fibers in the nerves of the lower leg changes significantly