The tricuspid valve is situated between the right atrium (top chamber) and the right ventricle (bottom chamber). Its function is to prevent back flow of blood into the right atrium. The tricuspid valve typically has three leaflets.
The pulmonary (or pulmonic) valve, which also has three leaflets, lies between the right ventricle and the pulmonary artery, where blood then flows to the lungs to pick up oxygen. When the valve is not functioning properly, blood from the valve flows back into the heart.