External auditory canal

A.Prof Frank Gaillard et al.

The external auditory canal (EAC) or external auditory meatus (EAM) extends from the lateral porus acusticus externus medially to the tympanic membrane.

As the term external auditory meatus (EAM) is variably used to refer to the canal or the porus acusticus externus (the round lateral opening) it may be better to use the term external auditory canal rather than meatus to avoid potential confusion. 

The EAC is typically 2.5 cm in length and is S-shaped. 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.

Anatomy: Head and neck
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Article information

rID: 6575
System: Head & Neck
Section: Anatomy
Synonyms or Alternate Spellings:
  • External auditory canal (EAC)
  • External acoustic canal (EAC)
  • External auditory meatus (EAM)
  • External auditory meatus
  • External acoustic canal
  • EAC
  • External acoustic meatus (EAM)
  • Ear canal
  • External acoustic meatus
  • EAM

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Cases and figures

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