A variant branch of the internal laryngeal nerve supplying filaments to the cricothyroid muscle: an autopsy case.

Abstract

We report a variant branch of the internal laryngeal nerve found in a Japanese male body. This branch, arising in the piriform fossa from the inferior portion of the loose network formed by the intercommunicating subbranches of the internal laryngeal nerve, descended in the interval between the thyroid and arytenoid cartilages accompanied by a branch of the superior laryngeal artery as far downward as the lowest portion of the thyroid cartilage. Here it crossed lateral to the inferior laryngeal nerve to which it gave off a communicating branch and reached the deep surface of the cricothyroid muscle. In this muscle it split into several divisions, each of which issued filaments to this muscle. The terminal branch of this variant branch ended in the fascia covering the cricothyroid muscle and the cricoid cartilage.