title: Shrapnell membrane and mastoid pneumatization.
abstract: OBJECTIVE
  To assess whether a correlation exists between the degree of pars flaccida (PF) retraction and the degree of mastoid pneumatization.
  
  
  METHODS
  The degree of PF retraction was defined by means of an operating microscope and a pneumatic otoscope. Degree of mastoid pneumatization was assessed planimetrically, using mastoid x-rays.
  
  
  METHODS
  Private otologic clinic.
  
  
  METHODS
  A total of 595 ears, with intact pars tensa, of 332 adult patients.
  
  
  RESULTS
  The degree of PF retraction was found to be inversely correlated to the level of mastoid pneumatization. Poorly pneumatized mastoids were associated with PF retractions. The poorer the pneumatization, the deeper the retraction. Well-pneumatized mastoids were associated with normal position of the PF.
  
  
  CONCLUSIONS
  This study lends further support to the possibility that the mastoid pneumatic system functions as a middle ear pressure buffer. This possibility gives further explanation as to why ears with poorly pneumatized mastoids tend to develop tympanic membrane retractions and perforations, incus necrosis, or retraction pocket cholesteatoma, while ears with a large pneumatic system are rarely at such risk.
authors.affiliation: Ear Research Laboratory, Sachler School of Medicine, Tel-Aviv, Israel.
authors.forename: J
authors.initials: J
authors.lastname: Sadé
authors.forename: C
authors.initials: C
authors.lastname: Fuchs
authors.forename: M
authors.initials: M
authors.lastname: Luntz
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D004427:Ear Diseases / Q000000981:diagnostic imaging / Q000473:pathology; D004432:Ear, Middle / Q000502:physiology; D006801:Humans; D008416:Mastoid / Q000000981:diagnostic imaging*; D011312:Pressure; D011859:Radiography; D014432:Tympanic Membrane / Q000033:anatomy & histology*