The morphology and topography of the superior laryngeal artery

Abstract

The aim of this study was to investigate and correlate the anatomical parameters of the superior laryngeal artery (SLA). For the study, 50 adult, human specimens were used; laryngeal pieces were drawn from 16 cadavers and the arteries were dissected intralaryngeally. In 68%, the SLA originated from the superior thyroid artery and in 32%, directly from the external carotid artery. In five sides, an aberrant superior laryngeal artery (ASLA) was entering the larynx through a foramen thyroideum. The normal superior laryngeal artery (NSLA) had a short extralaryngeal part and continued intralaryngeally, with two segments and a point of inflexion; the first segment ran along the superior border of the thyroid cartilage, the point of inflexion of the NSLA was at a minimal distance of 1.1 cm anterior to the superior horn of the thyroid cartilage and from this point the NSLA continued in the paraglottic space. The ASLA had a constant origin from the superior thyroid artery; it then traversed the foramen thyroideum and reached the paraglottic space-at the superior border of the lateral cricoarytenoid muscle, it ended in two terminal branches. We constantly evidenced the following collateral branches of the NSLA: superior, anterior and postero-medial. The terminal branches are the antero-inferior branches that constantly anastomose with the cricothyroid artery and the postero-inferior branch anastomosed with the inferior laryngeal artery. Occasionally, additional branches of the NSLA were found. In conclusion, the intralaryngeal branching patterns of the NSLA and the ASLA are similar, the differences being given by the entry point into the larynx that will make the superior and anterior branches of the ASLA longer, will eliminate the transversal segment of the NSLA, and will shorten the descending segment in the paraglottic space in the case of ASLA. The base of the upper horn of the thyroid cartilage, the oblique line and its tubercles, the cricothyroid membrane and the cricothyroid joint are constant landmarks that allow a precise intralaryngeal identification of the SLA. These findings can improve performances during surgical manipulations of the larynx and laryngeal transplants.