Venous outflow disorders refer to problems getting blood from the foot back to the heart. There are two sets of veins in the feet and legs to help bring the blood back toward the heart. The superficial venous network refers to veins located just beneath the skin. The deep venous networks are veins located closer to the bones and are not visible when looking at the foot or legs.
Varicose veins refer to an enlargement of the veins and a loss in the ability of the vein to properly maintain blood flow back toward the heart. When this occurs blood can collect in the feet and legs. Superficial varicose veins may appear as unsightly cords or a small bunch of grapes, which usually appear on the tops of the feet, around the ankles and may extend upward to the knees and thighs. Deep varicose veins while usually not visible will result in chronic swelling of the feet, ankles and legs. When the blood is not circulated from the feet back to the heart gravity will cause the fluid to collect in the feet and ankles. This results in swelling, called edema. Chronic edema over a long period of time may cause a discoloration of the skin around the ankles. The skin can become inflamed, and is know as venous stasis dermatitis. If left untreated the skin will become weakened and a weeping sore will develop, usually on the inside of the ankle called a venous stasis ulcer.
A potentially serious consequence of blood collecting in the feet and legs is the formation of blood clots in the veins. A superficial vein blood clot will result in a painful, inflamed superficial vein called superficial phlebitis. When a blood clot forms in a deep vein, it is called deep venous thrombosis, or deep phlebitis. This is a serious condition that causes painful swelling of the leg and may result in part of the clot breaking free. If the clot should travel back up to the heart and get caught in the lungs, it is referred to as a pulmonary embolus which can be life threatening and requires emergency treatment.