Persistent trigeminal artery communicating with a fetal posterior communicating artery: A case report.

A persistent trigeminal artery (PTA) is the most common carotid-vertebrobasilar anastomosis. PTA variants terminating on cerebellar arteries instead of the basilar artery have been reported previously. We present the first case of a PTA communicating with a fetal posterior communicating artery identified on a magnetic resonance angiogram. An understanding of these anatomical variants is important to clarify pathological processes that can help guide neurosurgical and endovascular procedures.