Anterior cardiac veins
The anterior cardiac veins (or anterior veins of right ventricle) comprise a variable number of small vessels, usually between two and five, which collect blood from the front of the right ventricle and open into the right atrium; the right marginal vein frequently opens into the right atrium, and is therefore sometimes regarded as belonging to this group. Unlike most cardiac veins, they do not end in the coronary sinus. Instead, these veins drain directly into the anterior wall of the right atrium.