A persistent primitive hypoglossal artery arising from the external carotid artery associated with subarachnoid hemorrhage.

Abstract

A persistent primitive hypoglossal artery (PHA) is a rare congenital caroticobasilar anastomosis with a reported prevalence of 0.027%-0.26%. Intracranial aneurysms occur with a frequency of approximately 26% in the setting of PHAs. PHAs typically originate from the proximal cervical internal carotid artery. To date, however, six cases of PHAs originating from the external carotid artery have been reported. We present the first case of a PHA originating from the external carotid artery associated with subarachnoid hemorrhage. We review the literature and discuss anatomic implications with respect to the extreme lateral infrajugular transcondylar exposure for clip ligation of a ruptured posterior inferior cerebellar artery aneurysm in the setting of a PHA.