title: Anatomic relationship between the facial nerve and the tympanic annulus.
abstract: OBJECTIVE
  To identify the relationship between the vertical portion of the facial nerve and the tympanic annulus, using computed tomographic (CT) scans of healthy adult and pediatric patients.
  
  
  METHODS
  A retrospective review of CT scans.
  
  
  METHODS
  The study was conducted in a tertiary referral medical center.
  
  
  METHODS
  After excluding ears with noted pathology, a total of 241 ears were included in the final review (121 right and 120 left ears). The mean age of the patients was 33.3 years (2 mo to 87 yr).
  
  
  METHODS
  Both structures were identified at three distinct locations: the superior and the inferior most margins of the tympanic ring and at the umbo. Measurements were made in both anteroposterior and a mediolateral planes. Comparisons between different age groups were made to analyze the relative change in position that happens with age.
  
  
  RESULTS
  The vertical portion of the facial nerve, as it proceeds distally, takes a more anterior and lateral course, and crosses the plane of the annulus almost consistently in the inferior third. The average distance at each location is reported. Statistically significant differences were found between age groups, in the areas around the second genu and the distal most segment of the facial nerve.
  
  
  CONCLUSIONS
  This is the largest anatomic study to date analyzing the relationship of the facial nerve to the tympanic annulus. It also allows comparison between age groups, demonstrating a significant difference between adult and pediatric groups, especially in the distal portion of the fallopian canal.
authors.affiliation: *Department of Otolaryngology Head and Neck Surgery, and †Department of Diagnostic Radiology, American University of Beirut Medical Center, Beirut, Lebanon.
authors.forename: Zaid Ali
authors.initials: ZA
authors.lastname: Zaghal
authors.forename: Roy Amin
authors.initials: RA
authors.lastname: Raad
authors.forename: Jihad
authors.initials: J
authors.lastname: Nassar
authors.forename: Roula
authors.initials: R
authors.lastname: Hourani-Rizk
authors.forename: Marc Kaissar
authors.initials: MK
authors.lastname: Bassim
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D002648:Child; D002675:Child, Preschool; D003627:Data Interpretation, Statistical; D016208:Databases, Factual; D004432:Ear, Middle / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000254:growth & development; D005154:Facial Nerve / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000254:growth & development; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D014057:Tomography, X-Ray Computed; D055815:Young Adult