title: Surface landmarks of the facial nerve trunk: a prospective measurement study.
abstract: BACKGROUND
  Facial nerve identification and preservation is the key to safe parotidectomy in most clinical situations. Traditional approaches to the main trunk have depended solely on internal landmarks but localization may further be enhanced if data are available on its position with reference to neighbouring external features.
  
  
  METHODS
  Prospective measurements were taken on a series of parotidectomy patients intraoperatively. Using that spot on the main trunk 10 mm proximal to its bifurcation as the reference point, the depth from the skin and its cranio-caudal distance from the summit of the tragus were measured.
  
  
  RESULTS
  Thirty-three patients were included, whose body mass index showed that they had average body build. The reference point nerve was 23.6 mm (SD = 5.1 mm) from the skin surface, and 18.8 mm (SD = 6.0 mm) caudal to the tragus.
  
  
  CONCLUSIONS
  Measurements relating to the siting of the facial nerve trunk were obtained live at operation. This information should be helpful in the initial mobilization of the parotid gland from its posterior relations and in facilitating the classical internal landmarks in the 3-D localization of the main trunk, thereby allowing quicker and safer parotidectomy.
authors.affiliation: Division of Head and Neck/Plastic and Reconstructive Surgery, Department of Surgery, University of Hong Kong Medical Centre, Queen Mary Hospital, Pokfulam, Hong Kong. wongsy@hku.hk
authors.forename: D S
authors.initials: DS
authors.lastname: Wong
mesh_terms: D000328:Adult; D000368:Aged; D005154:Facial Nerve / Q000033:anatomy & histology*; D020220:Facial Nerve Injuries / Q000209:etiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013517:Otorhinolaryngologic Surgical Procedures / Q000009:adverse effects / Q000379:methods; D010306:Parotid Gland / Q000601:surgery*; D010307:Parotid Neoplasms / Q000601:surgery