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Anterior inferior cerebellar artery

Dr Henry Knipe and Assoc Prof Frank Gaillard et al.

The anterior inferior cerebellar artery (AICA) is one of three vessels that provides arterial blood supply to the cerebellum. It has a variable origin, course and supply, with up to 40% of specimens not having an identifiable standard AICA. The amount of tissue supplied by the AICA is variable (AICA-PICA dominance) but usually includes:


99% of AICAs arise from the basilar artery, but where along the vessel is variable:

  • 75% lower third
  • 16% middle third
  • 9% vertebrobasilar junction


  • internal auditory branch (80% single, 20% double) passes into the IAM
  • lateral branch passes around the flocculus and into the hemispheric fissure (supplying both superior and inferior semilunar lobules)
  • medial branch supplies the biventral lobule

Before cross-sectional imaging, the AICA (along with venous displacement) was used to identify posterior fossa intra- or extra-axial masses, especially at the CP angle. Extra-axial masses (e.g. vestibular schwannomas or meningiomas) would displace the vessel whereas intra-axial masses tend not to.

Anatomy: Brain

Anatomy: Brain

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Article information

rID: 5014
Section: Anatomy
Tag: refs, artery
Synonyms or Alternate Spellings:
  • AICA
  • Anterior inferior cerebellar artery (AICA)

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Cases and figures

  • Figure 1: normal COW anatomy
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  • Figure 2: origin of the cerebellar arteries
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  • Figure 3: posterior fossa vascular territories
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  • Figure 4: mid-cerebellum
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  • Figure 5: PICA, AICA and SCA
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