The recurrent laryngeal nerve in relation to the inferior constrictor muscle of the pharynx.

The point of penetration of the recurrent laryngeal nerve into the larynx is recognized as the most frequent site of injury to the nerve during surgical procedures of the thyroid gland. The anatomical relationships of 25 right and left recurrent laryngeal nerves in 25 anatomical blocks from formalin-fixed human corpses have been studied. In 34 cases (68%), the recurrent laryngeal nerve penetrated into the larynx below the lower fibers of the inferior constrictor muscle of the pharynx (type 1 of penetration). In the remaining 16 cases (32%), the nerve crossed through those muscle fibers to penetrate into the larynx (type 2 of penetration). The thyroid gland was found to involve the recurrent laryngeal nerve at the penetration point into the larynx in 19 of 50 cases (38%).