The basilar artery provides blood to the brain. This artery and the two vertebral arteries comprise the vertebrobasilar system, which supplies blood to the posterior part of circle of Willis and connects (“anastomoses”) with blood supplied to the anterior part of the circle of Willis from the carotid arteries. It arises from the confluence of the two vertebral arteries, next to the lower brain stem, ascends parallel to the brain stem, and gives rise to the anterior inferior cerebellar artery, which supplies part of the cerebellum, some smaller branches that supply the brain stem, and the superior cerebellar artery. It finally divides into the two posterior cerebral arteries (PCA). These supply the upper brain stem, the occipital lobe, and the posterior portion of the temporal lobes.
The clinical manifestations of basilar artery occlusion depend on the location of the occlusion, the extent of thrombus, and the collateral flow. Normally, the blood flows in an...