<prompt> Which of the following does not directly drain into right atrium ?Great cardiac veinAnterior cardiac veinThebasian veinVenae cordis minimi  <response>: Great cardiac veinGreat cardiac vein does not directly drains into right atrium. It drains into coronary sinus, which in turn drains into right atrium.Veinous drainage of heaCoronary sinus : Opens into right atrium and has following tributries : i Great cardiac vein, ii Middle cardiac vein, iii Posterior vein of left ventricule, iv Small cardiac vein, v Oblique vein of left atrium and vi Sometimes right marginal vein.Anterior cardiac vein : Opens into right atrium.Venae cardis minimi thebasian veins : All these are extremely small veins in the walls of all the 4 