External auditory canal

The external auditory canal (EAC) extends from the tympanic membrane medially to the external auditory meatus (EAM) laterally. 

The external auditory meatus (EAM) may either refer to the canal or the round lateral opening of the EAC.

The EAC is typically 2.5 cm in length. The lateral 1.5 cm are bounded by a fibrocartilaginous tube continuous with the auricle. The medial 1 cm is formed by the bony margins of the temporal bone (the squamous part superiorly and the mastoid part posteriorly). The skin of this inner part is directly applied to periosteum, with no subcutaneous tissue present.

  • medially
  • laterally: external auditory meatus (EAM) surrounded by the pinna (auricle)
Head and neck anatomy
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Article information

rID: 6575
Tags: stub, refs, cases
Synonyms or Alternate Spellings:
  • External auditory canal (EAC)
  • external acoustic meatus
  • External acoustic canal (EAC)
  • External auditory meatus (EAM)
  • External auditory meatus
  • External acoustic canal
  • EAC
  • External acoustic meatus (EAM)
  • Ear canal

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Cases and figures

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    Figure 1: external ear anatomy (CT)
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    Case 1: external acoustic meatus (normal)
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