Persistent primitive trigeminal artery associated with monocular blindness and external carotid-vertebral artery anastomosis.

In this paper, we present 2 rare cases of persistent embryonic anastomoses. In one case, the patient presented with persistent trigeminal artery along with multiple foci of cerebral infarction as well as central retinal artery thrombosis. In the other case, the patient had direct anastomosis of the vertebral artery with ipsilateral external carotid artery as well as pontine infarction, aneurysm, and unilateral hypoplasia of the vertebral artery. The findings in these cases may shed light on the clinical presentation of such persistent anastomoses and aid their detection in clinical settings.