Anterior inferior cerebellar artery (AICA)
Artery in the brain that supplies part of the cerebellum.
From the lower part of BA, runs posterolaterally anterior to VI, VII & VIII. Often gives off a loop that runs into the IAC and gives off the labyrinthine artery and then emerges to supply the anterolateral inferior cerebellum and then anastomoses with PICA
The AICA lies near the surface of a vestibular schwannoma.
It arises from the lower part of the basilar artery at the level of the junction between the medulla oblongata and the pons in the brainstem.
Often gives off a loop that runs into the IAC and gives off the labyrinthine artery and then emerges to supply the anterolateral inferior cerebellum and then anastomoses with PICA.
It passes backward to be distributed to the anterior part of the undersurface of the cerebellum, anastomosing with the posterior inferior cerebellar branch of the vertebral artery.
Segments
Branches
Anterior inferior cerebellar artery branches.
Left side: AE: arcuate eminence; AICA: anteroinferior cerebellar artery; JB: jugular bulb; SC: semicircular canals; SCA: superior cerebellar artery; SPV: superior petrosal vein; SS: sigmoid sinus; VA: vertebral artery.
It supplies the anterior inferior quarter of the cerebellum.
It also gives off the labyrinthine artery in most cases; however, the labyrinthine artery can emerge as a branch of the basilar artery in others.
AICA: Anterior inferior cerebellar artery; C: Cerebellum; PB: Petrosal part of the temporal bone; SPV: Superior petrosal vein; SMT: Suprameatal tubercle; T: Tentorium;; V*: Motor roots of the trigeminal nerve.
Function
The anterior inferior cerebellar artery gives rise to the labyrinthine arteries which supply the vestibulocochlear and facial nerves. The anterior inferior cerebellar artery also supplies the lower lateral pons, the choroid plexus of the lateral ventricle, the middle cerebellar peduncle and the inferior anterior area of the cerebellum.
Variants
In about 99% of patients, the anterior inferior cerebellar artery arises from the basilar artery with about 75% of cases originating from the lower third. It may also stem from the vertebrobasilar junction as seen in about 9% of cases. The anterior inferior cerebellar artery has also been cited to give rise to the labyrinthine artery in about 90% of individuals. The most common variation noted is the presence no anterior inferior cerebellar artery, with its absence more common on the left side. In this variation, the anterior inferior cerebellar artery will either originate from a common trunk of the vertebral artery or the posterior inferior cerebellar arteries directly. Duplication of the anterior inferior cerebellar artery has also been noted but is rare. The double origin anterior inferior cerebellar artery has also been pointed out in the right anterior inferior cerebellar artery in which one branch originates from the basilar artery and the other from the vertebral artery. Some anastomoses have also been noted between the rostral part of the anterior inferior cerebellar artery and the superior cerebellar artery (SCA) and between the caudal part of the anterior inferior cerebellar artery and the posterior inferior cerebellar arteries. Other common variations that occur in the branches of the basilar artery that may affect the anterior inferior cerebellar artery are the agenesis of the right posterior inferior cerebellar arteries or the left posterior inferior cerebellar arteries. The agenesis of the posterior inferior cerebellar arteries may create an inverse relationship between the anterior inferior cerebellar artery and posterior inferior cerebellar arteries. In this case of the agenesis of the posterior inferior cerebellar arteries, there will be a well-developed anterior inferior cerebellar artery with the posterior inferior cerebellar arteries arising from an anterior inferior cerebellar artery/posterior inferior cerebellar arteries common trunk. The prevalence of this variation as reported in the literature is about 20% to 24% 1).