Stasis of the venous blood contributes to the formation of a blood clot or thrombus. As the thrombus grows along the axis of blood flow, part of it may break off and become an embolus that can lodge in downstream capillary beds and prevent blood flow to the served area. Most often emboli lodge in the pulmonary capillaries. When thrombosis occludes a vessel, collateral vessels may compensate. If collateral circulation is inadequate then edema can result.
Treatment includes anticoagulant therapy or surgical removal if the thrombus is large.
Inflammation of a vein, usually in the leg, due to the presence of a thrombus is called thrombophlebitis. Such inflammation can occur due to chemical damage, bacterial infection or from an unknown origin. Thrombophlebitis in deep veins of the legs causes calf pain and tenderness. Varicose veins Varicose veins are dilations of superficial veins caused by valve failures usually in the leg or groin area. For more information, please see Varicose-Vein.net .