<unk>  (from Ancient Greek "clotting”) is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel (a vein or an artery) is injured, the body uses platelets<unk> ocytes) and fibrin to form a blood clot to prevent blood loss. Even when a blood vessel is not injured, blood clots may form in the body under certain conditions. A clot, or a piece of the clot, that breaks free and begins to travel around the body is known as an embolus.<unk>  may occur in veins (venous<unk>  or in arteries (arterial<unk> . Venous<unk>  leads to congestion of the affected part of the body, while arterial<unk>  (and rarely severe venous<unk>  affects the blood supply and leads to damage of the tissue supplied by that artery (ischemia and necrosis). A piece of either an arterial or a venous<unk> us can break off as an embolus which can travel through the circulation and lodge somewhere else as an embolism. This type of embolism is known as a<unk> oembolism. Complications can arise when a venous<unk> oembolism (commonly called a VTE) lodges in the lung as a pulmonary embolism. An arterial embolus may travel further down the affected blood vessel where it can lodge as an embolism.
Thrombosis
Thrombus
Angiopathy
Sclerosis 
Calcification
Infarction
Adhesion 
Abscess