Association of two primitive carotid-basilar anastomoses and cerebrovascular abnormalities on the brain base: a case report.

Simultaneous presence of the persistent primitive trigeminal artery and so-called intermediate communicating artery in a 77-years-old cadaver autopsied due to the myocardial infarction was discovered. Many vascular variants and abnormalities such as an aplasia of the right vertebral artery (VA), a presence of two right posterior cerebral arteries (PCAs), partial duplication of the right superior cerebellar artery, hypoplasia of the pre-communicating part (A1) of the right anterior cerebral artery and the right PCA of basilar origin, a special configuration of the anterior communicating artery (ACoA), and a small aneurysm at the right A1-ACoA junction were associated. The finding of an incipient cerebral aneurysm at the junction of the hypoplastic A1 and embryonal configuration of the ACoA in eight decade of life indicates that its development was caused by long-term pressure of blood flow at branching points of this artery independent from its caliber. However, it is not yet clear whether the persistence of the first and/or the second carotid-basilar anastomoses in this case was the condition for an aplasia of one VA or vice versa.