Laryngeal nerve "anastomoses"

Abstract

Laryngeal nerves have been observed to communicate with each other and forma variety of patterns. These communications have been studied extensively and have been of particular interest as it may provide an additional form of innervation to the intrinsic laryngeal muscles. Variations noted in incidence may help explain the variable position of the vocal folds after vocal fold paralysis. This study aimed to examine the incidence of various neural communications and to determine their contribution to the innervation of the larynx. Fifty adult cadaveric en-bloc laryngeal specimens were studied. Three different types of communications were observed between internal and recurrent laryngeal nerves viz. (1) Galen's anastomosis (81%):in 13%, it was observed to supply the posterior cricoarytenoid muscle; (2) thyroarytenoid communication (9%): this was observed to supply the thyroarytenoid muscle in 2% of specimens and (3) arytenoid plexus (28%): in 6%, it supplied a branch to the transverse arytenoid muscle. The only communication between the external and recurrent laryngeal nerves was the communicating nerve (25%). In one left hemi-larynx, the internal laryngeal nerve formed a communication with the external laryngeal nerve, via a thyroid foramen. The neural communications that exist in the larynx have been thought to play a role in laryngeal innervation. The results of this study have shown varying incidences in neural communications. Contributions from these communications have also been noted to various intrinsic laryngeal muscles which may be a possible factor responsible for the variable position of the vocal folds in certain cases of vocal fold paralysis.