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Anatomical variations of the external branch of the superior laryngeal nerve in relation to the inferior constrictor muscle: cadaveric dissection study

  • U Patnaik (a1), A Nilakantan (a1) and T Shrivastava (a2)

Abstract

Objectives:

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.

Method:

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.

Results:

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.

Conclusion:

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.

Copyright

Corresponding author

Address for correspondence: Dr U Patnaik, Department of ENT, Base Hospital and Army College of Medical Sciences, Delhi Cantonment, New Delhi 110010, India Fax: +91 (0)112 333 7002 E-mail: umi75pat@gmail.com

References

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