Coronary veins accompany the coronary arteries and open into the right atrium.

The majority (75%) of the venous blood drains via the coronary sinus. The principle tributaries of the coronary sinus are the great, small, middle and posterior LV cardiac veins.

The anterior cardiac veins drain the anterior part of the RV directly to the RA.

Small veins drain directly into the cardiac chambers (thebesian veins).