Imaging of Congenital Anomalies and Developmental Abnormalities Involving the Arteries of the Head and Neck

The embryonic development of the cerebrovascular system is a highly intricate process that gives rise to the arterial network supplying the brain, one of the most metabolically demanding organs in the human body. A hallmark of this system is the presence of extensive collateral circulation, exemplified by the circle of Willis, which can preserve cerebral perfusion in the event of arterial occlusion, severe stenosis, or dissection. Disruptions in the embryologic development of this system can lead to a spectrum of congenital and developmental arterial anomalies. While many of these variants are asymptomatic, they may compromise compensatory circulation during cerebrovascular events and can alter hemodynamics, increasing the risk of conditions such as aneurysms. In this review, we provide a comprehensive overview of congenital and developmental anomalies affecting the arteries of the head and neck. We discuss their embryologic origins, prevalence, clinical implications, associated pathologies, and considerations for management. Representative imaging examples are included to support the recognition and interpretation of these vascular variants in clinical practice.