Ansa cervicalis and hypoglossal nerve topographical relation: anatomical study on cadavers.

Abstract

Ansa cervicalis and hypoglossal nerve are important neural structures of the neck. Their topographical disposition have important clinical and surgical implications. As described in a recent consensus, the ansa cervicalis originates in the spinal cord and then joins the hypoglossal awhile, without exchanging fibers, diverging from it to innervate the infrahyoid muscles. However, some dissection studies show individuals in which ansa cervicalis and hypoglossal nerve follow independent trajectories, diverging of classical characterization. This anatomical variation supports the need for better description of the link between these nerves and, therefore, improve surgical planning and technique. This project objective is to better characterize the relationship between ansa cervicalis and hypoglossal nerve, describing the percentage of link between these structures. In this regard, it will be realized a cross‐sectional study with 15 cadavers bilateral neck dissections. The study plans to analyze the data through nonparametric statistics. Our analysis will assess correlations between the topographic variety and sex, age, ethical and anthropometric characters of individuals. So far, we dissected 5 cadavers; of these 4 (80%) have ansa cervicalis not connected to hypoglossal nerve, meanwhile just 1 (20%) have this link. The project schedule predicts 10 more corpses dissections until January 2020. Until now, the small sample limit statistical analysis, but certainly it suggests there is a significant anatomical variant in the brazilian population. It is expected that our final results will contribute to better comprehension of these important neck structures and improve medical practice.