Which is the least common site for the occurance of berry aneurysm?
85% of berry aneurysms occur in the anterior circulation, mostly on the Circle of Willis. 3 most common anterior locations are over : anterior communicating aery, posterior communicating aery and middle cerebral aery. 10% of it occur over basilar aery and only 5% occur on veebral aery. Reference: Handbook of Neurosurgery By Mark Greenbergpage 1055.
Anterior communicating aery
Middle cerebral aery
Veebral aery
Basilar aery