Accessory middle cerebral artery: is it a variant form of the recurrent artery of Heubner?

Fourteen accessory middle cerebral arteries demonstrated on angiography were reviewed relative to the pertinent literature. The anomalous vessel follows a fairly constant pattern in terms of origin, course, and distribution, and it frequently gives rise to basal perforating arteries. It is suggested that the vessel represents a persistent anastomosis between the anterior and middle cerebral arteries over the tuberculum olfactorium, the anastomosis being a predecessor of the recurrent artery of Heubner in phylogenetic development. Among various descendants of the anastomotic channels could be included both the normal recurrent artery of Heubner and the accessory middle cerebral artery, with or without basal perforating arteries. We believe the simultaneous presence of the recurrent artery of Heubner and the accessory middle cerebral artery on one side may represent the persistence of two anastomoses, one as the recurrent artery of Heubner and the other as the accessory middle cerebral artery; this is similar to the situation of duplication of the recurrent artery of Heubner.