Topographic Anatomy of the Upper Laryngeal Nerve: Surgical Importance in Thyroidectomies

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Blás Antonio Medina-Ruíz; Joaquín Julián Medina-Izcurdia; Blás Agustín Medina-Izcurdia; Rocío Belén Martínez-Vera; Pedro Ramón Martínez-Vera; Clara Elba Izcurdia & Nicolás Ernesto Ottone


In surgeries on the thyroid gland, much attention has been given to the management of the inferior laryngeal nerve and parathyroid glands, but not the external branch of the given by the aforementioned nerve and the superior thyroid artery. This paper intends to study these relationships based on the meticulous dissection of the larynx-sternothyroid triangle (“Joll triangle”) of 25 formolized adult corpses. As a relevant finding, it is reported that the “nerves at risk” according to the Cernea classification, which is based on the distance less than one centimeter at the intersection of the nerve with the superior thyroid artery with respect to the upper pole of the gland, is 52 % for the right side and 44 % for the left side of the neck. The low origin of the artery at the level of the carotid bifurcation is associated with a greater number of “nerves at risk” on the left side. According to the penetration point of the external branch of the superior laryngeal nerve in the inferior pharyngeal constrictor muscle, the Friedman classification is established, very useful especially in surgeries aided by neurostimulation. In this classification the “nerves at risk” are those that run superficially to the muscle, while the protected nerves would be those that pierce the muscle in its upper part. In tis work, the “nerves at risk” presented on the left side in 56 % of the cases and the right side in 60 %, while those “protected” in 24 % and 16 % respectively.

KEY WORDS: External branch of the superior laryngeal nerve; Superior thyroid artery; Superior pole of the thyroid gland; Topographic anatomy.

How to cite this article

MEDINA-RUIZ, B. A.; MEDINA-IZCURDIA, J. J.; MEDINA-IZCURDIA, B. A.; MARTÍNEZ-VERA, R. B.; MARTÍNEZ- VERA, P. R.; IZCURDIA, C. E. & OTTONE, N. E.Topographic anatomy of the upper laryngeal nerve: Surgical importance in thyroidectomies. Int. J. Morphol., 38(4):766-773, 2020.