Idiopathic Occlusive Arterial Disorders in the Cervical Region and the Main Trunks of the Cerebral Arteries in Japan

sion of the tumor, the anterior and the middle cerebral arteries were normally visualized through the posterior cerebral arteries and the rami splenii in the vertebral angiogram. 7) Angiographic examination of a case of 10 year-old boy which was followed-up for a period of 5 years revealed that the collaterals from the rete mirabile became more and more richer with a remarkable decrease in the juxtabasal vascular networks. If the vascular networks are functioning as collaterals, they should increase in vascularity as his age progresses and, therefore, the fact that the vascular networks gradually decrease is very much in favor of its congenital origin. The hypoplasia of the distal portion of the carotid siphon and the peculiar