The innervation of the human larynx
I. Sanders, B. L. Wu, L. Mu, Y. Li and H. F. Biller
Grabscheid Voice Center, Department of Otolaryngology, Mount Sinai Medical Center, New York, NY.
OBJECTIVE: To investigate the gross anatomy of the recurrent and superior
laryngeal nerves (RLNs and SLNs) in 10 human larynges. METHODS: Whole
larynges were processed to clear all soft tissue while leaving nerves
stained. Then the main laryngeal nerves and the muscles they innervate were
dissected and analyzed. RESULTS: It was found that in all larynges the RLNs
and SLNs are connected by nerve branches other than Galen's anastomosis.
The most consistent connection is in the interarytenoid muscle, where RLNs
and internal SLNs combine in a neural plexus. A less consistent connection
occurs in the piriform fossa, where a continuation of the external SLN
passes from the cricothyroid muscle to the thyroarytenoid muscle.
CONCLUSION: Based on these findings it is proposed that there are
significant neural connections between the RLN and SLN systems. In
addition, limited cross-innervation is seen from side to side in the area
of the interarytenoid muscle. Other findings concern the innervation
patterns within the laryngeal muscles. The posterior cricoarytenoid,
cricothyroid, and thyroarytenoid muscles all appear to be composed of
separate bellies based on the configuration of their nerve supply. Most
notable is the region of the thyroarytenoid muscle at the vocal cord margin
that is innervated by a nerve plexus of extreme complexity. The details of
the innervation patterns suggest functional differences within and between
laryngeal muscles.
