(anatomy) An artery that usually branches from the vertebral artery below its junction with the contralateral vertebral artery to form the basilar artery and that supplies much of the medulla oblongata, the inferior portion of the cerebellum, and part of the floor of the fourth ventricle.

(anatomy) An artery that arises from the basilar artery either alone or by a common trunk with the labyrinthine artery, divides into branches distributed to the anterior parts of the inferior surface of the cerebellum, and gives off a branch that anastomoses with the posterior inferior cerebellar artery.