"origin: vertebral artery confluence"
"course: ventral to pons in the pontine cistern"
"branches: numerous to cerebellum and pons"
"termination: division into the two posterior cerebral arteries"
"variants: basilar artery fenestration; persistent carotid-basilar artery anastomoses"
"variants: basilar artery fenestration; persistent carotid-basilar artery anastomoses"
"labyrinthine artery (variable origin; more commonly a branch of AICA)"