Coronary Sinus

The coronary (coronary) sinuses are two anatomical structures that open into the right atrium on its posterior wall near the mouth of the superior vena cava. The name “coronary” is due to the fact that the sinuses drain blood from the coronary vessels of the heart into the cardiac cavity, becoming branches of the great coronary vein, which flows into the left atrium and then mixes with the blood entering through the pulmonary veins and venous blood that bends around to the left. Often these anatomical formations are called coronary sinuses, from which 3–6 liters of blood flow into the right atrium. Both sinuses are formed by the rectus anterior muscle, which stretches from the xiphoid process to the jugular notch. The sinuses cross the right atrioventricular foramen (“ausupification” of the small foramen, as in the inferior vena cava).