The right auricle of the heart - also called the right atrial appendage (RAA) - is attached to the heart's right atrium. It's a small, cone-shaped pouch which comes out from the upper and front part of the atrium and overlaps the root of the aorta. The RAA is very muscular, and is lined with small muscles on its surface. It collects deoxygenated blood from the bloodstream and moves it into the heart's right ventricle.