Which venous structure does not empty blood into the right atrium

The coronary sinus is the venous structure that does not empty blood into the right atrium. The coronary sinus is a collection of veins joined together to form a large vessel that collects blood from the heart muscle (myocardium). It receives blood mainly from the small, middle, great and oblique cardiac veins. It also receives blood from the left marginal vein and the left posterior ventricular vein.

Dis the answer hope this

1.controls blood flow2.controls oxygen flow3.carries oxygen rich blood to veins