title: A histological study of scala communis with radiological implications.
abstract: OBJECTIVE
  Scala communis or interscalar septum (IS) defect is a developmental abnormality of the inner ear characterized by a dehiscence in the partition separating the turns of the cochlea. The goals of the present study were to (1) study this anomaly and describe its characteristics compared to control ears using a histological analysis of temporal bones, (2) discuss radiological implications regarding its diagnosis, and (3) describe its embryological derivation.
  
  
  METHODS
  Out of 1775 temporal bones assessed, 22 specimens were found to have scala communis in cochleae containing all 3 turns (basal, middle and apical). These 22 ears were studied in detail by qualitative and quantitative methods using light microscopy.
  
  
  RESULTS
  Scala communis occurred as an isolated inner ear anomaly, or in association with other congenital cochlear and/or vestibular anomalies. The defect occurred most often between the middle and apical turns of the cochlea. Compared to control ears, scala communis ears were found to have a smaller modiolar area (p < 0.0001) and flattening of the interscalar ridge (point of attachment of the IS to the inner lumen of the cochlea; p < 0.0001). Scala communis was compatible with normal hearing.
  
  
  CONCLUSIONS
  Flattening of the interscalar ridge has the potential to improve the diagnosis of scala communis in patients using CT scanning. The anomaly may result from a mesodermal defect such as excessive resorption of mesenchyme during the formation of the scalae, an error in the formation of bone, or both.
authors.affiliation: Department of Otolaryngology, Massachusetts Eye and Ear Infirmary and Harvard Medical School, Boston, Mass. 02114, USA. Chadi_Makary @ meei.harvard.edu
authors.forename: Chadi
authors.initials: C
authors.lastname: Makary
authors.forename: Jennifer
authors.initials: J
authors.lastname: Shin
authors.forename: Paul
authors.initials: P
authors.lastname: Caruso
authors.forename: Hugh
authors.initials: H
authors.lastname: Curtin
authors.forename: Saumil
authors.initials: S
authors.lastname: Merchant
mesh_terms: D007758:Ear, Inner / Q000002:abnormalities* / Q000000981:diagnostic imaging*; D006801:Humans; D012372:ROC Curve; D011859:Radiography; D013701:Temporal Bone / Q000002:abnormalities* / Q000000981:diagnostic imaging*
references.citation: Laryngoscope. 2002 Dec;112(12):2230-41
references.pmid: 12461346
references.citation: J Acoust Soc Am. 1996 Sep;100(3):1602-16
references.pmid: 8817890
references.citation: Ann Otol Rhinol Laryngol Suppl. 1980 Mar-Apr;89(2 Pt 3):1-10
references.pmid: 6769379
references.citation: Int J Pediatr Otorhinolaryngol. 2002 Mar 15;63(1):29-39
references.pmid: 11879927
references.citation: Clin Otolaryngol Allied Sci. 1990 Apr;15(2):99-101
references.pmid: 2350896
references.citation: Otol Neurotol. 2004 Jul;25(4):520-9; discussion 529
references.pmid: 15241231
references.citation: Ann Otol Rhinol Laryngol Suppl. 1980 Jan-Feb;89(1 Pt 2):1-23
references.pmid: 6767432
references.citation: AMA Arch Otolaryngol. 1953 Jun;57(6):591-602
references.pmid: 13057434
references.citation: AMA Arch Otolaryngol. 1953 Oct;58(4):377-97
references.pmid: 13091542
references.citation: Laryngoscope. 1978 Aug;88(8 Pt 1):1231-46
references.pmid: 672357
references.citation: Laryngoscope. 1987 Mar;97(3 Pt 2 Suppl 40):2-14
references.pmid: 3821363