RESUMO
Persistent proatlantal artery (PPA) is a rare embryologically remnant carotico-vertebrobasilar anastomoses. There are two types of PPA according to embryological considerations, origin and anatomic course. Type I PPA usually originate from internal carotid artery and not traversing transverse foramen. Type II PPA traverses from external carotid artery to C1 transverse foramen. The PPA is usually found incidentally without clinical symptoms, but can be related to several clinically significant vascular lesions, such as hypoplastic vertebral artery, intracranial arteriovenous malformation and in a case of carotid endarterectomy or external carotid artery embolization. So, thorough understanding of this anomaly is needed and we report a case of type II PPA diagnosed by MR angiography.