Anterior inferior cerebellar artery

At a glance

English

Anterior inferior cerebellar artery

Latin (TA2)

Arteria cerebelli inferior anterior

System

Artery

Region

Head

Side

Paired, left and right

About the anterior inferior cerebellar artery

The anterior inferior cerebellar artery, often shortened to AICA, is the middle of the three cerebellar arteries on each side. It usually springs from the lower part of the basilar artery, close to where the pons meets the medulla oblongata, just after the two vertebral arteries have joined.

From its origin it runs backwards and laterally across the front of the pons towards the cerebellopontine angle. Its course is variable, but here it has close relations with the facial and vestibulocochlear nerves, often forming a loop near the internal acoustic meatus. In most people it gives off the labyrinthine artery, which accompanies those nerves into the meatus to the inner ear, though in some the labyrinthine artery comes straight from the basilar. The vessel then turns onto the anterior part of the inferior surface of the cerebellum.

Its territory is the front of the cerebellar undersurface, together with the flocculus, the middle cerebellar peduncle and the lower lateral part of the pons, and through the labyrinthine artery the inner ear. This area grows or shrinks depending on the size of the posterior inferior cerebellar artery below it, with which it anastomoses, as it does with the superior cerebellar artery above.

Blockage is uncommon but causes the lateral inferior pontine (AICA) syndrome. Patients have sudden vertigo, vomiting and nystagmus, slurred speech, and a tendency to fall towards the affected side. On that same side there is limb ataxia, loss of all forms of facial sensation, facial palsy, and deafness with tinnitus; pain and temperature sense are lost from the opposite limbs and trunk. The deafness and marked facial weakness help separate it from the lateral medullary syndrome. Brief vertigo may come before the stroke, probably from passing ischaemia of the inner ear.

Course and supply

Arises from

The basilar artery, near its lower end at the junction of the pons and the medulla oblongata.

Ends in

Ends on the anterior part of the inferior surface of the cerebellum, anastomosing with the posterior inferior and superior cerebellar arteries.

Supplies

Supplies the anteroinferior cerebellum, the flocculus, the middle cerebellar peduncle, the inferolateral pons and, usually through the labyrinthine artery, the inner ear.