title: Branching pattern of the external branch of the superior laryngeal nerve and its clinical importance.
abstract: The external branch of the superior laryngeal nerve gives off many branches above the upper pole of the thyroid gland. Differentiating the branch innervating the cricothyroid muscle from the others may be important during surgery. Therefore, we aimed to demonstrate the branching pattern of this nerve in detail. In 34 human cadavers (59 sides), branches of the nerve were exposed and measurements related to them and neighboring structures were made. A cricothyroidal branch was present on all sides. This branch pierced the inferior pharyngeal constrictor muscle 3.9-17.6 mm above, 3.1-9.9 mm below, or at the level of the upper pole of the thyroid gland. On all sides, the nerve provided one or two thyroidal branches. The thyroidal branch was generally thinner than the cricothyroidal branch. But they were equal in size on three (5%) sides. The external laryngeal nerve provided two or three pharyngeal branches on all sides. These branches arose from the nerve 3.5-12.7 mm from the upper pole of the thyroid gland. Although the branch was generally thinner than the cricothyroidal branch, both branches were equal on four (6.7%) sides. Two cardiac branches were observed on two (3.3%) left sides. In conclusion, the cricothyroidal branch was generally thicker than the other branches. But on seven (11.8%) sides, thyroidal or pharyngeal branches and the cricothyroidal branch were equal in size. These data may be important during surgery as the surgeon may confuse the cricothyroidal branch with other branches of the external laryngeal nerve.
authors.affiliation: Department of Anatomy, Gulhane Military Medical Academy, Ankara, Turkey. drbyalcin@yahoo.com
authors.forename: Bulent
authors.initials: B
authors.lastname: Yalcin
authors.forename: R Shane
authors.initials: RS
authors.lastname: Tubbs
authors.forename: Abdullah
authors.initials: A
authors.lastname: Durmaz
authors.forename: Ayhan
authors.initials: A
authors.lastname: Comert
authors.forename: Mehmet
authors.initials: M
authors.lastname: Toygar
authors.forename: Marios
authors.initials: M
authors.lastname: Loukas
authors.forename: Sedat
authors.initials: S
authors.lastname: Develi
mesh_terms: D006801:Humans; D007823:Laryngeal Nerves / Q000033:anatomy & histology*; D012016:Reference Values