title: Identification of three anatomical patterns of the spinal accessory nerve in the neck by neurophysiological mapping.
abstract: BACKGROUND
  In spite of preservation of the accessory nerve there is still considerable proportion of patients with partial nerve damage during modified radical neck dissection (MRND).
  
  
  METHODS
  The nerve was identified during the surgery and its branches for the trapezius muscle mapped with nerve monitor.
  
  
  RESULTS
  The accessory nerve was mapped during 74 hemineck dissections and three patterns were identified. In type 1 nerve exits at the posterior end of the sternocleidomastoid muscle (SCm) and then it enters the level V (66%). In type 2 the nerve for trapezius muscle branches off before entering the SCm (22%). In type 3 the nerve exits at the posterior part of the SCm and it joins to the cervical plexus (12%). The nerve than exits this junction more medially as a single trapezius branch.
  
  
  CONCLUSIONS
  The description of three anatomical patterns in level II and V could help preserving the trapezius branch during MRND.
authors.affiliation: Department of Otorhinolaryngology, Cervical and Maxillofacial Surgery, University Medical Center Maribor, Slovenia.
authors.forename: Bostjan
authors.initials: B
authors.lastname: Lanisnik
authors.affiliation: Department of Otorhinolaryngology and Cervicofacial Surgery, University Medical Center Ljubljana, Slovenia.
authors.forename: Miha
authors.initials: M
authors.lastname: Zargi
authors.affiliation: Institute of Clinical Neurophysiology, University Medical Center Ljubljana, Slovenia.
authors.forename: Zoran
authors.initials: Z
authors.lastname: Rodi
keywords: anatomy; neck dissection; nerve mapping; shoulder disability; spinal accessory nerve