Sock line, ankle swelling caused by vein disease, Twin Cities Minnesota[/caption] The veins in your legs are responsible for moving blood up to the lager veins in the torso of the body where it is then returned to the heart.  These leg veins have valves that prevent the backward flow of blood within them.  Venous reflux or insufficiency means there is incompetence of the vein valves and this occurs because of vein dilation or enlargement and or dysfunction of vein valves.  This happens, for example, in the patients with varicose veins.  Venous insufficiency leads to a backup of blood and increased pressure in the veins, thereby resulting in swelling or edema of the legs, ankles and or feet.  Edema of the legs also can occur with an episode of deep vein thrombosis, which is a blood clot within a vein.  In this situation, the clot in the deep vein blocks the return of blood, and consequently causes increased back-pressure in the leg veins. Venous insufficiency is a problem that is localized to the legs, ankles and feet.  One leg may be more affected than the other (asymmetrical swelling or edema).  In contrast, systemic diseases that are associated with fluid retention generally cause the same amount of edema in both legs, and can also cause edema and swelling elsewhere in the body.  The response to therapy with diuretic drugs in patients with venous insufficiency tends to be unsatisfactory.  This is because the continued pooling of fluid in the lower extremities makes it difficult for the diuretics to mobilize the edema fluid.  Elevation of the legs periodically during the day and the use of compression stockings may alleviate the edema. If you are concerned about lower extremity (leg, ankle and or foot) swelling, an ultrasound evaluation may help to find answers.  Complete an online assessment or contact Minnesota Vein Center for answers.