Persistent primitive trigeminal artery: a review.

The trigeminal artery is the largest of the fetal carotid-basilar anastomotic arteries, and it persists for the longest embryonic period. The artery usually involutes after the development of the posterior communicating artery. The exact causes of persistence of this primitive vessel into adulthood are not completely clear. Angiographic and anatomical descriptions of the various persistent trigeminal artery (PTA) configurations and their relation to the remainder of the cerebrovascular tree and the other surrounding structures have been reported. Persistent trigeminal artery can be associated with many other vascular anomalies and disorders including aneurysms, arteriovenous malformations and carotid-cavernous fistulae. A thorough understanding of the anatomical and angiographic features of this persistent embryonic arterial channel is of utmost importance when making therapeutic decisions and embarking on surgical or endovascular intervention for any pertinent pathological condition. We review the embryology, angiographic features, microsurgical anatomy and associated vascular anomalies and disorders of the persistent trigeminal artery.