WASHINGTON, DC - JANUARY 20: U.S. President Donald Trump delivers his inaugural address on the West Front of the U.S. Capitol on January 20, 2017 in Washington, DC. In today's inauguration ceremony Donald J. Trump becomes the 45th president of the United States.
One-Way Valves in the Veins. One-way valves consist of two flaps (cusps or leaflets) with edges that meet. These valves help veins return blood to the heart. As blood moves toward the heart, it pushes the cusps open like a pair of one-way swinging doors (shown on the left).
Below is a basic outline of the anatomy and function of the veins and what constitutes venous incompetence. Be aware however that there are numerous anatomical variations. Valves. 1  The veins contain a series of valves along their course, preventing retrograde flow back down the leg.2  These valves operate like two plastic doors opening up the leg. 3  If back pressure is applied, they swing closed, pushing against each other, blocking reverse flow down the leg. The veins contain a series of valves along their course, preventing retrograde flow back down the leg. 2  These valves operate like two plastic doors opening up the leg. 3  If back pressure is applied, they swing closed, pushing against each other, blocking reverse flow down the leg.