Aneurysm of the anterior communicating artery associated with accessory middle cerebral artery--case report.

A 63-year-old female presented with an anterior cerebral artery aneurysm associated with accessory middle cerebral artery. The aneurysm was located on one of the duplicate anterior communicating arteries, and the accessory middle cerebral artery originated from the anterior cerebral artery adjacent to this aneurysm. The recurrent artery of Heubner was not recognized. The accessory middle cerebral artery may have been involved in the genesis of the aneurysm by changing the hemodynamics in the anterior cerebral arteries.