Varicose veins are twisted, enlarged veins near the surface of the skin that most commonly develop in the legs. As the heart pumps blood filled with oxygen and nutrients to the whole body, arteries carry blood from the heart towards the body parts. Veins carry oxygen-poor blood from the body back to the heart. The squeezing of leg muscles pumps blood back to the heart from the legs. Veins have valves that act as one-way flaps. These valves prevent blood from flowing backwards as it moves up the legs. If the one-way valves become weak, blood can leak back into the vein and pool in the vein. This problem is called venous insufficiency. This poorly, backward flowing blood enlarges the vein and it becomes varicose.
Certain genetic factors and lifestyles can make some people more likely to develop varicose veins with heredity being the primary factor. Aging, obesity, and pregnancy as well as occupations that require standing can aggravate the situation. In most situations, varicose veins simply "happen" like so many other diseases. All of the aforementioned conditions may not actually cause varicose veins--but they can make them occur earlier in life and/or make them worse. It is a chronic disease that may never be completely "cured," but with proper care and follow up, it can be easily controlled.