Which is the least common site for the occurance of berry aneurysm?: (A) Anterior communicating aery, (B) Middle cerebral aery, (C) Veebral aery, (D) Basilar aery
Answer is C. 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.