Topography of the inferior alveolar nerve in human embryos and fetuses. An histomorphological study.

Sergey Lvovich Kabak,Natallia Victorovna Zhuravleva,Yuliya Michailovna Melnichenko

doi:10.17126/joralres.2017.082

Sergey Lvovich Kabak, Natallia Victorovna Zhuravleva + Show 1 more

Open Access

https://doi.org/10.17126/joralres.2017.082

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Abstract

Abstract: The aim of this study is to establish the position of the inferior alveolar nerve in relation to the Meckel’s cartilage, the anlage of the mandibular body and primordia of the teeth, and also to trace the change in nerve trunk structure in the human prenatal ontogenesis. Serial sections (20µm) from thirty-two 6-12 weeks-old entire human embryos and serial sections (10µm) of six mandibles of 13-20 weeks-old human fetuses without developmental abnormalities were studied. Histological sections were impregnated with silver nitrate according to Bilshovsky-Buke and stained with hematoxylin and eosin. During embryonic development, the number of branches of the inferior alveolar nerve increases and its fascicular structure changes. In conclusion, the architecture of intraosseous canals in the body of the mandible, as well as the location of the foramina, is predetermined by the course and pattern of the vessel/nerve branching in the mandibular arch, even before the formation of bony trabeculae. Particularly, the formation of the incisive canal of the mandible can be explained by the presence of the incisive nerve as the extension of the inferior alveolar nerve. It has also been established that Meckel’s cartilage does not participate in mandibular canal morphogenesis.

Highlights

The inferior alveolar nerve is one of the terminal branches of the mandibular nerve
The mylohyoid nerve and the mental nerve are located outside the mandible, whereas the dental branches originate in the bone
The aim of the study is to establish the position of the inferior alveolar nerve in relation to the Meckel’s cartilage, the anlage of the mandibular body and primordia of the teeth, and to trace the change in nerve trunk structure in human prenatal ontogenesis

Summary

Introduction

After exiting the cranium through foramen ovale, it lies posterior and lateral to lingual nerve; it enters the mandibular canal, in which it is accompanied by the artery and vein of the same name, as well as lymphatic vessels.[1] The branches of the inferior alveolar nerve are the mylohyoid nerve and the mental nerve that along with the dental branches form the inferior dental plexus. The mylohyoid nerve and the mental nerve are located outside the mandible, whereas the dental branches originate in the bone. According to the literature there are several types of branching of the inferior alveolar nerve inside the bone.[2] In most of the cases it is one thick trunk, which splits into two terminal branches in the region of the mental foramen: the mental and incisive nerves. The branches innervating lower molars and the second premolar start from the inferior alveolar nerve before branching into its terminal subdivisions.

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