This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anatomy
Which of the following does not drain into coronary sinus: March 2009 
Select and explain. 
A. Anterior cardiac vein, B. Small cardiac vein, C. Middle cardiac vein, D. Great cardiac vein
A: Anterior cardiac vein
Answer: A: Anterior cardiac vein 
Explanation: Coronary sinus receives blood mainly from the small, middle, great and oblique cardiac veins.It also receives blood from the right marginal vein and the left posterior ventricular vein.Most blood from the hea wall drains into the right atrium through the coronary sinus, which lies in the posterior pa of the atrioventricular.It opens into the right atrium to the left of the inferior vena cava.The anterior cardiac veins drain directly into the right atrium