Anastomosis of Carotid and Basilar Arteries

I N THE 3 mm human embryo, the internal carotid artery is seen to anastomose with the basilar artery by the primitive trigeminal, otic, and hypoglossal arteries from above down. 13 These vascular channels are usually obliterated by the time the embryo is 14 mm long. Should any of these primitive channels persist into adult life, the result is referred to as a persistent carotidbasilar anastomosis. We are reporting one case with a persistent primitive trigeminal artery and another with a persistent hypoglossal artery arising from the external carotid artery.