STRUCTURE AND POSITION :

•         Right Atrium is further divided into two parts. An Auricle (now known as Right Atrial Appendage) is a flap of skin on anterior surface. And main part known as Sulcus, which contains the cavity of the atrium.
•         Right Atrium collects deoxygenated blood from Inferior Vena Cava, Superior Vena cava, Coronary Sinus and Smallest Cardiac Veins. All these structures have separate openings inside the Atrium.
•         Right Atrium opens into the Right Ventricle through a Tricuspid Valve. Tricuspid Valve is a three cusps valve which allows blood flow only towards the Ventricle.
•         Right Atrium has smooth internal walls with Sinus Venarum at the openings of the aforementioned vessels. It is a smooth walled portion of the inner wall of the Right Atrium.
•         Inter-Atrial Septum separates the two Atria of the Heart and has a depression over this wall known as Fossa Ovalis.
•         Crista Terminalis is a ridge like structure which separates the two layers (muscular and smooth) of the Right Atrium.

FUNCTION :

Right Atrium receives deoxygenated blood from the whole Body and Heart itself and send it to Right Ventricle. Tricuspid Valve maintains direction of flow of blood from Right Atrium to the Right Ventricle. Right Ventricle pumps this blood to the Pulmonary Circulation (lung circulation) for Oxygenation.