Trumpeted internal acoustic meatus sign

A.Prof Frank Gaillard et al.

A trumpeted internal acoustic meatus (IAM) is an indirect sign of an acoustic schwannoma and is useful in helping to differentiate between one and other cerebellopontine angle entities, especially from a meningioma which typically does not extend into the meatus and is more often associated with hyperostosis 1.

It is characterized by widening of the medial end of the internal acoustic canal and porus acusticus resulting in an appearance reminiscent of a trumpet.

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Article information

rID: 2216
Section: Signs
Tag: refs, stub
Synonyms or Alternate Spellings:
  • Trumpeted IAM sign

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Cases and figures

  • Figure 1: trumpet (photo)
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  • Case 1
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  • Case 2: trumpeted IAM
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  • Case 2: normal IAM for comparison
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