The size, number, and distribution of nerve endings around and within the human epiglottis, focusing on tracheal intubation maneuvers

Abstract

The aim of this study was to examine the distribution of nerve endings in the mucosa, submucosa, and cartilage of the epiglottis and the vallecula area and to quantify them. The findings could inform the choice of laryngoscope blades for intubation procedures. Fourteen neck slices from seven unembalmed, cryopreserved human cadavers were analyzed. The slices were stained, and cross and longitudinal sections were obtained from each. The nerve endings and cartilage were identified. The primary metrics recorded were the number, area, and circumference of nerve endings located in the mucosa and submucosa of the pharyngeal and laryngeal sides of the epiglottis, epiglottis cartilage, and epiglottic vallecula zone. The length and thickness of the epiglottis and cartilage were also measured. The elastic cartilage of the epiglottis was primarily continuous; however, it contained several fragments. It was covered with dense collagen fibers and surrounded by adipose cells from the pharyngeal and laryngeal submucosa. Nerve endings were found within the submucosa of pharyngeal and laryngeal epiglottis and epiglottic vallecula. There were significantly more nerve endings on the posterior surface of the epiglottis than on the anterior surface. The epiglottic cartilage was twice the length of the epiglottis. The study demonstrated that the distribution of nerve endings in the epiglottis differed significantly between the posterior and anterior sides; there were considerably more in the former. The findings have implications for tracheal intubation and laryngoscope blade selection and design.