Bypass anomaly of the vertebral artery associated with cerebral aneurysm and arteriovenous malformation

✓ In a series of 1107 patients with cerebrovascular disease studied by four-vessel angiography, the authors have found 10 cases of a bypass anomaly of the vertebral artery. Six of the cases also had cerebral aneurysms, and two cerebral arteriovenous malformations. The authors discuss the possible origins for this relationship.