Embryology of the cerebral vasculature.

Although much remains to be learned about the embryology of the intracranial vasculature, much of the developmental pathways of the intracranial vascular system are now apparent. Understanding these pathways offers the potential to appreciate the nature of such arterial anomalies as the azygos anterior cerebral artery and the trigeminal artery and such venous anomalies as the vein of Galen malformation and the venous angioma.