The artery formed by the union of the right and left vertebral arteries; it runs from the lower to the upper border of the pons, where it bifurcates into the two posterior cerebral arteries.
An artery which lies at the base of the brain.
An artery in the base of the brain, formed by the union of the two vertebral arteries. It extends from the lower to the upper border of the pons Varolii and then divides to form the two posterior cerebral arteries.
An artery formed from the union of the left and right vertebral arteries. It supplies blood to the cerebellum, brainstem, and posterior portions of the cerebellum. Strokes involving this artery can damage the cerebellum and parts of the brainstem that regulate essential vegetative functions (e.g., consciousness and respiration).