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Anterior inferior cerebellar artery

contributed by Dr Frank Gaillard on November 17, 2008

Systems: Vascular
Central Nervous System
Section: Anatomy

The anterior inferior cerebellar artery (AICA) is one of three vessels that provides arterial blood supply to the cerebellum. It has a variable origin, and 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 (PICA - AICA dominance) but usually includes:

  • middle cerebellar peduncle
  • infrolateral portion of the pons
  • flocculus
  • anteroinferior surface of the cerebellum

Origin

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

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

Branches

  • 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 acoustic schwannomas or meningiomas) would displace the vessel whereas intra-axial masses tended not to.