This article waslast modified on July 10, 2017.

Embolism— a condition in which material (tissue, fat, air, blood clot, etc.—called an embolus) travels through the bloodstream and then becomes lodged in a vein or artery and blocks the flow of blood through that blood vessel.

Thromboembolism—a blood clot (thrombus) that breaks free in the blood stream and blocks a blood vessel. This can occur in a vein (venous thromboembolism) or in an artery (arterial thromboembolism).