THE INNERVATION OF THE HUMAN LARYNX

Objective: To investigate the gross anatomy of the recurrent and super ior laryngeal nerves (RLNs and SLNs) in 10 human larynges. Methods: Wh ole larynges were processed to clear all soft tissue while leaving ner ves stained. Then the main laryngeal nerves and the muscles they inner vate were dissected and analyzed. Results: It was found that in all la rynges the RLNs and SLNs are connected by nerve branches other than Ga len's anastomosis. The most consistent connection is in the interaryte noid muscle, where RLNs and internal SLNs combine in a neural plexus. A less consistent connection occurs in the piriform fossa, where a con tinuation of the external SLN passes from the cricothyroid muscle to t he thyroarytenoid muscle. Conclusions: Based on these findings it is p roposed that there are significant neural connections between the RLN and SLN systems. In addition, limited cross-innervation is seen from s ide to side in the area of the interarytenoid muscle. Other findings c oncern the innervation patterns within the laryngeal muscles. The post erior cricoarytenoid, cricothyroid, and thyroarytenoid muscles all app ear to be composed of separate bellies based on the configuration of t heir nerve supply. Most notable is the region of the thyroarytenoid mu scle at the vocal cord margin that is innervated by a nerve plexus of extreme complexity. The details of the innervation patterns suggest fu nctional differences within and between laryngeal muscles.