If you have an open sore on your leg that just won't go away, it might be a venous ulcer. Venous ulcers, also known as venous stasis ulcers or varicose ulcers, are wounds that occur when there's poor circulation due to vein disease or venous insufficiency, typically in the legs. Other symptoms of vein disease include swelling in the legs or ankles, cramps in the thighs or calf, and unsightly veins.