title: Radiological patterns of the posterior semicircular canal.
abstract: OBJECTIVE
  The identification and definition of the radiological patterns of the posterior semicircular canal (PSC), with a view to obtain readily applicable conclusions.
  
  
  METHODS
  The parietal morphology of the PSC has been studied by multi-slice helical computed tomography (Philips Brilliance 6). We have determined the distribution of the different types of bone cover of the PSC, taking some previously notified, standardised measurements of normality as reference.
  
  
  RESULTS
  318 patients have been analysed (604 petrous bone) by CT and we have distinguished five different radiological patterns: type or normal, thick, thin, pneumatised and dehiscent. The first three patterns, normal, thick and thin, have in common the existence of a compact bone interposed between PSC and posterior fossa, being in the normal pattern has a thickness of between 0.9 and 2.5 mm (327 cases, 54.13%), in the thick pattern is ≥2.6 mm (99 cases, 16.39%) and in the thin pattern is ≤1.2 mm (158 cases, 26.15%). The fourth pattern, pneumatised, is characterised by having retro labyrinthine cells between PSC and media fossa (19 cases, 3.14%). Finally, a dehiscent pattern was observed in 2 cases (0.3%).
  
  
  CONCLUSIONS
  We describe five different radiological patterns: type or normal, thick, thin, pneumatised and dehiscent. The thin type (<0.5 mm or papyraceous type) and the dehiscent type would be subject to producing pathology, and in some cases the latter could be a consequence of the former.
authors.affiliation: Department of Human Anatomy and Histology, School of Medicine, University of Zaragoza, C/Domingo Miral, s/n, 50009, Zaragoza, Spain, aicisner@unizar.es.
authors.forename: Ana Isabel
authors.initials: AI
authors.lastname: Cisneros
authors.forename: Jaime
authors.initials: J
authors.lastname: Whyte
authors.forename: Claudio
authors.initials: C
authors.lastname: Martínez
authors.forename: Borja
authors.initials: B
authors.lastname: Gracia-Tello
authors.forename: Ana
authors.initials: A
authors.lastname: Whyte
authors.forename: Jesús
authors.initials: J
authors.lastname: Obón
authors.forename: Rafael
authors.initials: R
authors.lastname: Crovetto
authors.forename: Miguel Ángel
authors.initials: MÁ
authors.lastname: Crovetto
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010579:Petrous Bone / Q000000981:diagnostic imaging; D012665:Semicircular Canals / Q000000981:diagnostic imaging*; D013030:Spain; D036542:Tomography, Spiral Computed / Q000379:methods*; D055815:Young Adult