Microtia refers to a small pinna of the ear, when is it completely absent it is termed anotia.


The estimated incidence at around 1:9000 live births. It is more common in males and there is a recognized right sided predilection.



Microtia can be associated with a wide spectrum of inner and middle ear anomalies 1. Isolated microtia is relatively uncommon. The most frequent associations include: 

Wider organ associations include:

Syndromic associations include:


It is classified into four grades based on increasing severity:

  • grade I: slightly small ear with identifiable structures; external auditory canal small but present
  • grade II: partial or hemiear with a occluded or stenotic external ear canal producing a conductive hearing loss 
  • grade III: absence of the external ear with a small peanut like vestige structure and an absence of the external ear canal and eardrum
  • grade IV: complete absence (anotia)
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Article information

rID: 10710
System: Head & Neck
Synonyms or Alternate Spellings:
  • Micro-otia

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Cases and figures

  • Left EAC atresia
    Case 1: grade III on left
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  • Case 2
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  • Case 3
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