The Coronary Sinus (CS) is the largest cardiac venous structure. Anterior interventricular vein, great cardiac vein, left marginal vein and posterior vein and middle cardiac vein or posterior interventricular veins are the main branches of CS. The average width of the CS, which varies with width, it ranges from 5 mm to 16 mm at the level of the ostium. The thebesian valves, where the CS opens into the right atrium, protect the CS. Small valves may also be found between the veins that meet along the coronary venous system [1-4].

It is commonly accessed for cardiac interventional procedures [1-3]. Therefore, their variations and pathologies must be recognized by radiologists.