Variations of the accessory nerve: anatomical study including previously undocumented findings-expanding our misunderstanding of this nerve

R. Shane Tubbs, Olaide O. Ajayi, Fabian N. Fries, Robert J. Spinner, Rod J. Oskouian

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Introduction: The anatomy of the accessory nerve has been well described but continued new clinical and anatomical findings exemplify our lack of a full understanding of the course of this nerve. Therefore, this study aimed to expand on our knowledge of the course of the 11th cranial nerve via anatomical dissections. Methods: Fifty-six cadavers (112 sides) underwent dissection of the accessory nerve from its cranial and spinal origins to its emergence into the posterior cervical triangle. Immunohistochemistry was performed when appropriate. Results: Our findings included two cases (1.8%) where the nerve was duplicated, one intracranially and one extracranially. One accessory nerve (0.9%) was found to enter its own dural compartment within the jugular foramen. The majority of sides (80%) were found to have a cranial root of the accessory nerve. Thirty-one sides (28%) had connections to cervical dorsal roots medially and three sides (2.7%) laterally. Medial connections were most common with the C1 nerve. Medial components of these dorsal root connections were all sensory in nature. However, lateral components were motor on two sides (1.8%). Nerves traveled anterior to the internal jugular vein on 88% of sides. One (0.9%) left side nerve joined an interneural anastomosis between the dorsal rootlets. Macroganglia were found on the spinal part of the intracranial nerve on 13% of sides. The lesser occipital nerve arose directly from the accessory nerve on two sides (1.8%) and communicated with the accessory nerve on 5.4% of sides. One side (0.9%) was found to communicate with the facial nerve with both nerves innervating the sternocleidomastoid muscle. Conclusions: Additional anatomical knowledge of the variants of the accessory nerve may benefit patient care when this nerve is pathologically involved.

Original languageEnglish (US)
Pages (from-to)113-115
Number of pages3
JournalBritish Journal of Neurosurgery
Volume31
Issue number1
DOIs
StatePublished - Jan 2 2017

Fingerprint

Accessory Nerve
Spinal Nerve Roots
Dissection
Cranial Nerves
Jugular Veins
Facial Nerve
Cadaver
Anatomy
Patient Care
Neck
Immunohistochemistry
Muscles

Keywords

  • Anatomy
  • cranial nerve
  • neck
  • posterior cranial fossa
  • spine
  • surgery

ASJC Scopus subject areas

  • Surgery
  • Clinical Neurology

Cite this

Variations of the accessory nerve : anatomical study including previously undocumented findings-expanding our misunderstanding of this nerve. / Tubbs, R. Shane; Ajayi, Olaide O.; Fries, Fabian N.; Spinner, Robert J.; Oskouian, Rod J.

In: British Journal of Neurosurgery, Vol. 31, No. 1, 02.01.2017, p. 113-115.

Research output: Contribution to journalArticle

Tubbs, R. Shane ; Ajayi, Olaide O. ; Fries, Fabian N. ; Spinner, Robert J. ; Oskouian, Rod J. / Variations of the accessory nerve : anatomical study including previously undocumented findings-expanding our misunderstanding of this nerve. In: British Journal of Neurosurgery. 2017 ; Vol. 31, No. 1. pp. 113-115.
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abstract = "Introduction: The anatomy of the accessory nerve has been well described but continued new clinical and anatomical findings exemplify our lack of a full understanding of the course of this nerve. Therefore, this study aimed to expand on our knowledge of the course of the 11th cranial nerve via anatomical dissections. Methods: Fifty-six cadavers (112 sides) underwent dissection of the accessory nerve from its cranial and spinal origins to its emergence into the posterior cervical triangle. Immunohistochemistry was performed when appropriate. Results: Our findings included two cases (1.8{\%}) where the nerve was duplicated, one intracranially and one extracranially. One accessory nerve (0.9{\%}) was found to enter its own dural compartment within the jugular foramen. The majority of sides (80{\%}) were found to have a cranial root of the accessory nerve. Thirty-one sides (28{\%}) had connections to cervical dorsal roots medially and three sides (2.7{\%}) laterally. Medial connections were most common with the C1 nerve. Medial components of these dorsal root connections were all sensory in nature. However, lateral components were motor on two sides (1.8{\%}). Nerves traveled anterior to the internal jugular vein on 88{\%} of sides. One (0.9{\%}) left side nerve joined an interneural anastomosis between the dorsal rootlets. Macroganglia were found on the spinal part of the intracranial nerve on 13{\%} of sides. The lesser occipital nerve arose directly from the accessory nerve on two sides (1.8{\%}) and communicated with the accessory nerve on 5.4{\%} of sides. One side (0.9{\%}) was found to communicate with the facial nerve with both nerves innervating the sternocleidomastoid muscle. Conclusions: Additional anatomical knowledge of the variants of the accessory nerve may benefit patient care when this nerve is pathologically involved.",
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