title: Pars flaccida retraction and mastoid size: relationship in clinically normal specimens.
abstract: BACKGROUND
  The relationship of pars flaccida retraction with epitympanic aeration and mastoid size is ill-defined. Both pars flaccida retraction and small mastoid size are traits of nearly all clinical entities of otitis media.
  
  
  OBJECTIVE
  To determine, in clinically normal specimens, the relationship of pars flaccida retraction with mastoid pneumatisation and epitympanic aeration.
  
  
  METHODS
  Post-mortem anatomical dissection of 41 bequeathed adult crania without clinical otitis.
  
  
  METHODS
  Pars flaccida retractions were viewed with an operating microscope and judged using Sade's classification. Mastoid sizes were determined radiographically (by plain Law lateral images). Ten crania, five with the largest mastoids and five with the smallest mastoids, were studied by computed tomography.
  
  
  RESULTS
  No specimen had a retraction worse than Sade grade two (i.e. retracted onto the neck of the malleus). Retractions were unrelated to the extent of mastoid pneumatisation. All epitympani were found to be normal on both anatomical dissection and computed tomography imaging.
  
  
  CONCLUSIONS
  Pars flaccida retraction is probably related to prior, presumably transient, non-aeration of Prussak's space.
authors.affiliation: Temporal Bone Laboratory, Emory University, Atlanta, Georgia 30322, USA. ntodd@emory.edu
authors.forename: N W
authors.initials: NW
authors.lastname: Todd
mesh_terms: D000886:Anthropometry / Q000379:methods; D006801:Humans; D008416:Mastoid / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D010033:Otitis Media / Q000473:pathology*; D011312:Pressure; D011859:Radiography; D015203:Reproducibility of Results; D014432:Tympanic Membrane / Q000033:anatomy & histology* / Q000000981:diagnostic imaging