All the following vessels end directly in the right atrium except
Superior vene cava, inferior vene cava,coronary sinus, anterior cardiac veins ,vene cordis minimi. these are the veins that directly open to right atrium. BD CHAURASIA'S HUMAN ANATOMY.VOLUME 1.6 TH EDITION.PAGE NO 255
Coronary sinus
Oblique vein of left atrium
Anterior cardiac vein
Venae cordis minimae
Thorax