Anatomical Course of the Thyroarytenoid Branch of the Recurrent Laryngeal Nerve

Objectives/Hypothesis To determine the position and anatomic variability of the thyroarytenoid (TA) branch of the recurrent laryngeal nerve (RLN) in an Indian population. This study is specifically targeted to aid in identifying the nerve for reinnervation procedures for unilateral and bilateral vocal fold paralysis, as well as denervation surgeries such as TA myoneurectomy and Selective Laryngeal Adductor Denervation and Reinnervation (SLAD-R) for adductor spasmodic dysphonia. Methods We dissected 46 fresh-frozen adult larynges (92 sides) without pathology. A window was created in the thyroid cartilage lamina. The intralaryngeal part of the dissection was done using magnification with an ocular loupe. The position and direction of the nerve and branching within the cartilage window were noted. Results The TA nerve was found to emerge from the posteroinferior quadrant of the cartilage window, irrespective of the dissected side (right/left) and gender in all of the 46 larynges. The nerve traveled in an oblique direction in 29 specimens (63.04%) and in a vertical direction in 17 specimens (36.96%). The orientation of the nerve was the same on the two sides of the larynx in all of the specimens. Branching was seen within the cartilage window in eight larynges (17.39%). Conclusions Knowledge of the possible variabilities in the course of the TA nerve aids in its localization while avoiding trauma to the posterior branch of the RLN that innervates the posterior cricoarytenoid and is responsible for vocal fold abd