A histological study of scala communis with radiological implications

Chadi Makary, Jennifer Shin, Paul Caruso, Hugh Curtin, Saumil Merchant

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Objectives: 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.

Original languageEnglish (US)
Pages (from-to)383-393
Number of pages11
JournalAudiology and Neurotology
Issue number6
StatePublished - Sep 2010
Externally publishedYes


  • Cochlea
  • Inner ear anomalies
  • Mesoderm
  • Mondini defect
  • Scala communis

ASJC Scopus subject areas

  • Physiology
  • Otorhinolaryngology
  • Sensory Systems
  • Speech and Hearing


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