Ruptured aneurysm at the origin of the accessory middle cerebral artery: case report.

The accessory middle cerebral artery is a rare vascular anomaly of the brain. We describe a case of a ruptured aneurysm at the junction of the accessory middle cerebral artery and the horizontal portion of the anterior cerebral artery. The lesion was demonstrated by angiography and confirmed at surgery. No perforating arteries arising from this accessory artery were found. There have been only four previous reports of aneurysms located at the origin of the accessory middle cerebral artery. The relevant literature is briefly reviewed.