Laryngeal branches of the recurrent laryngeal nerve: A narrative review of human anatomical studies

The recurrent laryngeal nerve (RLN) provides motor innervation to all intrinsic laryngeal muscles except the cricothyroid. Detailed knowledge of its terminal branching is essential for thyroid, laryngeal, and voice surgeons. This review synthesizes existing human cadaveric and surgical descriptions of the extralaryngeal and motor branching of the RLN, with attention to functional and clinical implications. Prior to laryngeal entry, the RLN most commonly bifurcates into an anterior (motor) and posterior (sensory) branch, with extralaryngeal branching identified in approximately 60% of nerves across large pooled series; bifurcation accounts for roughly half of all cases and typically occurs 1-2 cm inferior to the cricothyroid articulation. The motor division of the RLN is organized into vertical, genu, and oblique segments. The posterior cricoarytenoid muscle, the sole abductor of the true vocal fold, is innervated first and exhibits at least three distinct branching configurations, with further complexity arising from compartmental innervation patterns. The adductor muscles-arytenoid, lateral cricoarytenoid, and thyroarytenoid-are innervated sequentially, with the branches to the latter two representing the true terminal branches of the RLN. These branches form a complex anastomotic network with the superior laryngeal nerve, including Galen's anastomosis and the arytenoid plexus. Current anatomical knowledge derives predominantly from small cadaveric series; further studies are needed for characterization of these structures with greater resolution and clinical applicability.