Are the interarytenoid muscles supplied by branches of both the recurrent and superior laryngeal nerves?

Objectives/HypothesisIt has been generally accepted that the branches of the internal branch of the superior laryngeal nerve to the interarytenoid muscle are exclusively sensory. However, some experimental studies have suggested that these branches may contain motor axons, and therefore that the interarytenoid muscle is supplied by both the superior and recurrent laryngeal nerves. The aim of this work was to determine whether motor axons to the interarytenoid muscles are present in both laryngeal nerves. Study DesignBasic research. MethodsTwelve human internal branches of the superior laryngeal nerve were dissected, and its branches to the interarytenoid muscle were removed and processed for choline-acetyltransferase immunohistochemistry, a method not used previously in studying the nerve fiber composition of the laryngeal nerves. ResultsThe internal branch of the superior laryngeal nerve divided into two to five branches to the interarytenoid muscle. All branches contained motor axons, with the proportion of motor axons varying from 6% to 31%. ConclusionThe present study confirms that the internal branch of the superior laryngeal nerve provides a motor innervation to the interarytenoid muscles. Level of EvidenceN/A. Laryngoscope, 126:1117-1122, 2016