The surface is somewhat irregular, and there are areas of pale tan to white admixed with dark red areas.The thrombus often has the outlines of the vein in which it formed.

• 尽管携带大部分血和氧气的肺动脉被切断，但发自循环系统的分支动脉(供应肺大约1%25的血)并没被切断，因此出血性梗死相对来说不易发生。