Lacunar infarctions are small subcortical infarcts, <1.5 cm in diameter, within deep areas of the brain. Roughly 1 in 5 strokes are estimated to be lacunar strokes.

The cerebellum is supplied with blood via three branches of the basilar artery – the posterior inferior cerebellar artery (PICA), the anterior inferior cerebellar artery (AICA), and the superior cerebellar artery (SCA).

The image shows how the blood supply of the brain is arranged. The internal carotid arteries branch to form two major cerebral arteries on each side. The posterior circulation to the brain is mediated by the vertebral arteries.

There are often differences between anterior, middle, and posterior cerebral artery infarctions.