It's as thick as a thumb. 简直和拇指一样粗

577. Their arms have to be ready to fall off.
     胳膊都要断掉了
578. Look at the size of this artery.
     看看这条动脉
579. My god.
     我的天啊
580. It's as thick as a thumb.
     简直和拇指一样粗
581. You ever seen a vessel this size?
     你见过这么粗的血管吗
582. No.
     没有
583. This thing's just feeding on all her blood.
     这东西需要大量供血

来自《实习医生格蕾 第一季 第六集 Grey's Anatomy S01E06》第 580 行