4038 Trifurcation of basilar artery

Introduction The anatomy of the posterior circulation is very complex and variable. The basilar artery which forms the spine of posterior cerebral circulation usually terminates by dividing into two posterior cerebral arteries [1]. Basilar termination is the most frequent site of aneurysm [2]. The variations may also alter the relationships with and compress oculomotor nerve [3]. There are, however, few reports on variant termination of the basilar artery. These variations are related to the pattern of origin of superior cerebellar artery [4]. Trifurcation of basilar artery is very rarely reported and the knowledge of this variation might be important clinically in cerebelllopontine angle and clivus surgery.