The tricuspid valve forms the boundary between the right ventricle and the right atrium. Deoxygenated blood enters the right side of the heart via the inferior and superior vena cava.These are large veins that transport deoxygenated blood from the body back to the heart.ight atrioventricular valve (Tricuspid valve). The tricuspid valve forms the boundary between the right ventricle and the right atrium. Deoxygenated blood enters the right side of the heart via the inferior and superior vena cava. These are large veins that transport deoxygenated blood from the body back to the heart.