Which artery is least likely to harbor a berry aneurysm among PCA, ACA, MCA, and ICA?

Which artery is least likely to harbor a berry aneurysm among PCA, ACA, MCA, and ICA?

• A. PCA
• B. ACA
• C. MCA
• D. ICA

Answer: (A)

Berry aneurysms form most often at branch points in the Circle of Willis where wall stress concentrates and there may be inherent vessel wall weakness. The anterior communicating artery is the most common site, with the middle cerebral artery at its bifurcation and the internal carotid artery regions (including the junctions near the posterior communicating artery) also being frequent locations. The posterior cerebral artery itself has fewer high-stress branching points, so aneurysms there are comparatively rare. Therefore, the posterior cerebral artery is the least likely to harbor a berry aneurysm among the options.

Berry aneurysms form most often at branch points in the Circle of Willis where wall stress concentrates and there may be inherent vessel wall weakness. The anterior communicating artery is the most common site, with the middle cerebral artery at its bifurcation and the internal carotid artery regions (including the junctions near the posterior communicating artery) also being frequent locations. The posterior cerebral artery itself has fewer high-stress branching points, so aneurysms there are comparatively rare. Therefore, the posterior cerebral artery is the least likely to harbor a berry aneurysm among the options.