Patnaik U, Nilakantan A, Shrivastava T
Department of ENT, Base Hospital and Army College of Medical Sciences, New Delhi, India.
J Laryngol Otol. 2012 Sep;126(9):907-12. doi: 10.1017/S0022215112001454. Epub 2012 Jul 12.
To determine anatomical variations in the external branch of the superior laryngeal nerve in relation to the inferior constrictor muscle, and to propose a rational approach for the preservation of the nerve in thyroid surgery based on anatomical principles.
A cadaveric dissection study of the anatomy of the external branch of the superior laryngeal nerve in relation to the inferior constrictor muscle was conducted. Twenty-nine formalin-fixed cadavers of both sexes (age 50-70 years), with normal necks, were examined.
In relation to the Friedman classification, three anatomical variations of the external branch of the superior laryngeal nerve were found. Type 1 variation was found in 57.1 per cent of cases, type 2 in 26.8 per cent and type 3 in 16 per cent.
The prevalence of type 3 variation of the external branch of the superior laryngeal nerve suggests that the nerve will not be encountered in a certain percentage of individuals as it lies under the cover of the inferior constrictor. Therefore, there is no justification for attempting to identify the nerve in all cases.
确定喉上神经外支相对于咽下缩肌的解剖变异，并基于解剖学原理提出甲状腺手术中保留该神经的合理方法。
进行了一项关于喉上神经外支与咽下缩肌关系的尸体解剖研究。检查了29具（年龄50 - 70岁）颈部正常的男女福尔马林固定尸体。
根据弗里德曼分类法，发现喉上神经外支有三种解剖变异。1型变异见于57.1%的病例，2型见于26.8%，3型见于16%。
喉上神经外支3型变异的发生率表明，在一定比例的个体中，该神经位于咽下缩肌下方，不会被遇到。因此，没有理由在所有病例中都试图识别该神经。
