左肺肺动脉内大血栓。这类血栓多见于长期卧床病人的下肢深静脉或骨盆静脉。其它的不利因素包括四肢损伤、高凝状态(癌症病人患Trousseaus综合症；蛋白质 C 或 S 缺乏；使用口服避孕药)，心衰，怀孕，年龄大。
Seen in the pulmonary artery to the left lung on cut section is a large pulmonary thromboembolus. Such thromboemboli typically originate in the leg veins or pelvic veins of persons who are immobilized. Other contributing factors include trauma to the extremities, hypercoagulable states (Trousseaus's syndrome in patients with carcinomas; protein C or S deficiency; use of oral contraceptives), heart failure, pregnancy, and older age.
