Varicose veins: Also known as Venous Stratis Disease. The leg and thigh muscles assist the heart in blood circulation just like most large muscles in the body. They are involved in pumping blood against gravity back to the heart with the help of valves that close to avoid a backward flow. Pressure as a result of a large abdomen may increase the work load on the valves eventually causing damage. Damaged valves then allow for blood to back up, due to gravity, causing high pressure in these veins leading to swelling, thickening of skin and skin ulcers.