Thrombosis (from Greek "thrombus") is the formation of a blood clot (thrombus) inside a blood vessel, obstructing flow of blood through the circulatory system.

• When a blood vessel is injured, the body uses platelets and fibrin to form a blood clot to p revent blood loss
• Even when a blood vessel is not injured, blood clots may form in the body under certain conditions
• Embolus is where a clot breaks free and begins to travel around the body. Thromboembolism is the combination of thrombosis and its main complicatino, embolism. TED is shorthand for thromboembolic disorder
• When a thrombus is significantly large enough to reduce blood flow to tissue, it causes hypoxia (oxygen deprivation), and metabolic products (e.g. lactic acid) can accumulate
• A larger thrombus can cause greater obstruction to blood, resulting in anoxia (i.e. complete deprivation of oxygen) and infarction (tissue death)

• Virchow's triad, including:
  • Hypercoagulability
  • Endothelial cell injury
    Disturbed blood flow