The vessels draining Myocardium of the heart join to form Coronary Sinus that ultimately opens into THE RIGHT ATRIUM.
The heart muscles are called as Myocardium. Circulation of myocardium is known as Coronary Circulation. The heart needs to work continuously and requires an uninterrupted supply of blood.
Coronary Arteries supply oxygen rich blood to the myocardium and Coronary Veins remove deoxygenated blood from heart muscles and join to form Coronary Sinus that ultimately drains into the Right Atrium of heart. Some veins from the myocardium also drains directly into the right atrium.