[Case report: Aneurysm of the Rt-vertebral artery which terminates as the Rt-posterior inferior cerebellar artery (author's transl].

A case aneurysm of the Rt-vertebral artery which terminates as the Rt-posterior inferior cerebellar artery is reported. It belongs to rare anomalies that one of two vertebral arteries terminates as the posterior inferior cerebellar artery of the same side, though various anomalies arise very often in a vertebral artery system. Such an anomaly had been recognized in approximately 0.2% among vertebral angiographies. We had experienced 4 such anomalous cases among 501 vertebral angiographies which had been performed in our neurosurgery clinic from the beginning of 1967 to the end of June of 1973. A case among them had an aneurysm at a distal portion, the other one had a tumor. The process of the origin of such an anomaly is briefly discussed.