title: Quantitative ultrasonography of facial muscles.
abstract: BACKGROUND
  There is no standardized method for examination of facial muscles with ultrasound. The purpose of this study was to identify those facial muscles accessible for reliable identification and to provide reference data.
  
  
  METHODS
  In healthy subjects all facial muscles were screened for visibility, separation from adjacent muscles, and reliability of landmarks. Bilateral scans of reliable muscles were performed in 40 adult volunteers.
  
  
  RESULTS
  Six facial muscles were clearly demarcated with ultrasound. These were: frontalis, orbicularis oculi, orbicularis oris, depressor anguli oris, depressor labii inferioris, and mentalis muscles. Cross-sectional area and muscle thickness showed gender differences and were independently related to age for some muscles. A significant left-right side difference was only seen for the orbicularis oculi muscle in women.
  
  
  CONCLUSIONS
  These data demonstrate the usefulness of ultrasonography to assess facial muscles and provide reference values that can be applied in the clinical setting.
authors.affiliation: Department of Otorhinolaryngology, Jena University Hospital, Lessingstrasse 2, D-07740 Jena, Germany.
authors.forename: Gerd Fabian
authors.initials: GF
authors.lastname: Volk
authors.forename: Nadja
authors.initials: N
authors.lastname: Wystub
authors.forename: Martin
authors.initials: M
authors.lastname: Pohlmann
authors.forename: Mira
authors.initials: M
authors.lastname: Finkensieper
authors.forename: Heather J
authors.initials: HJ
authors.lastname: Chalmers
authors.forename: Orlando
authors.initials: O
authors.lastname: Guntinas-Lichius
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019412:Anatomy, Cross-Sectional; D005152:Facial Muscles / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D012016:Reference Values; D015203:Reproducibility of Results; D014463:Ultrasonography; D055815:Young Adult