在黑色卡片标出的白色箭头代表 Willis环上破裂的颅底小动脉瘤的部位。这是蛛网膜下腔出血的一介主要原因。
The white arrow on the black card marks the site of a ruptured berry aneurysm in the circle of Willis. This is a major cause for subarachnoid hemorrhage.