A 42-year-old woman collapses with sudden severe headache and neck stiffness. CT shows subarachnoid hemorrhage. Angiography reveals a saccular aneurysm arising from the circle of Willis. Which artery is the most frequent site of rupture?

• A Posterior inferior cerebellar artery
• B Posterior communicating artery
• C Basilar artery tip
• D Anterior communicating artery ✓

Explanation

Berry (saccular) aneurysms occur at branch points of the circle of Willis where the media is congenitally thin, and the most common single site is the anterior communicating artery. The basilar tip and posterior communicating artery are recognized but less frequent sites. Rupture causes subarachnoid hemorrhage rather than intraparenchymal bleeding, distinguishing it from hypertensive hemorrhage.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.