Cochlear aplasia

Cochlear aplasia, or complete absence of the cochlea is a rare anomaly which accounts for only 3% of cochlear malformations.1

  • complete absence of the cochlea. Dense otic bone is seen at the anatomical site of the cochlea 2
  • cochlear nerve canal and cochlear nerve are absent
  • cochlear promontory is hypoplastic and flattened
  • the vestibule and semicircular canals are often malformed, stunted, dilated but may be normal
  • vestibular aqueduct is normal
  • internal auditory canal usually hypoplastic
  • facial nerve canal usually anomalous showing obtuse angle anterior genu
  • middle ear is usually normal sized with normal ossicles
  • oval window usually normal but may be atretic 
  • labyrinthitis ossificans:
    • normal-sized bone is seen anterior to the IAC
    • the bulge of the cochlear promontory produced by the basal turn of the cochlea is present
  • common cavity deformity
  • cystic cochleovestibular anomaly
  • labyrinthine aplasia

Cochlear anomalies (classification)

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Article information

rID: 47542
System: Head & Neck
Section: Pathology
Tag: cases
Synonyms or Alternate Spellings:

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