Primitive intracranial arteries, including the trigeminal, proatlantal, otic, hypoglossal, and stapedial arteries, are embryonic vascular structures that temporarily connect the anterior and posterior, or intracranial and extracranial, circulations before typically regressing during development. Their persistence into adulthood, although rare, may alter local haemodynamics, contributing to aneurysm formation, vessel stenosis, or cranial nerve dysfunction. However, given the low incidence of associated pathologies, the mere presence of a persistent primitive anastomosis is not considered a concern for aneurysm formation. The persistent trigeminal artery is the most commonly observed persistent intracranial artery, with an incidence rate of up to 0.6%. It is followed by the persistent hypoglossal artery, present in 0.02–0.09% of cases, and the persistent proatlantal artery, with an incidence of 0.03%, while others, such as the otic and stapedial arteries, are exceptionally rare. Each persistent anastomosis has distinct embryological origins, anatomical variants, and potential roles in cerebrovascular compensation. Although persistent arteries may serve as collateral pathways in cases of cerebrovascular stenosis or occlusion, they can also pose risks during neurosurgical and endovascular procedures. Given their potential association with vascular pathologies in some cases, precise recognition of these arteries via imaging is essential to prevent misdiagnosis and optimise therapeutic strategies. This study provides a comprehensive review of the embryology, anatomy, and clinical relevance of persistent primitive intracranial arteries, aiming to enhance understanding, facilitate diagnosis, and improve treatment planning in cerebrovascular interventions.

embryonic cerebral vasculature, persistent anastomoses, carotid-vertebrobasilar anastomoses