Reliable surgical landmarks for the identification of the recurrent laryngeal nerve

To obtain reliable landmarks for identification of the recurrent laryngeal nerve in human larynges.

This is a prospective study, analyzing the laryngeal anatomic features. Structures easily palpable on the thyroid and cricoid cartilage (ie, the most prominent portion of the inferior cornu of the thyroid cartilage [IC], the inferior tubercle of the thyroid cartilage [ITT] and the most anterior portion of the arch of the cricoid cartilage [AC]) were accepted as landmarks and the distances of these structures to the entrance point of the RLN on the medial aspect of the inferior pharyngeal constrictor muscle (cross point [CP]) were measured in 65 adult autopsies.

When a straight line is drawn 11 to 12 millimeters (mm) from the IC, 22 to 24 mm from the ITT, and 26 to 28 mm from the AC, the point at which they intersect indicates the point at which the RLN enters the medial side of the inferior pharyngeal constrictor muscle (ICM) and is easy to locate at this point. All of the RLN were seen to lie posterolateral to the Berry ligament. Thirty-eight of 65 cases possessed extralaryngeal bifurcation of the RLN.

With such constant mathematic values, these 3 landmarks are reliable markers for identification of RLN. This study is important in the fact that it states constant mathematic values regarding surgical landmarks used to expose the RLN.