Name the major veins that drain the myocardium into the coronary sinus.

• A. Inferior vena cava, superior vena cava, and azygos vein
• B. Great cardiac vein, middle cardiac vein, and small cardiac vein
• C. Great cardiac artery, middle cardiac artery, and small cardiac artery
• D. Obstructed coronary veins cause myocardial ischemia

Answer: (B)

The veins that drain the myocardium into the coronary sinus are the major cardiac veins that collect most of the heart's venous blood and deliver it to the coronary sinus, which then empties into the right atrium. The prominent ones are the great cardiac vein, which runs along the anterior interventricular sulcus and then in the coronary sulcus to join the coronary sinus; the middle cardiac vein, located in the posterior interventricular sulcus and also draining into the coronary sinus; and the small cardiac vein, which travels in the right marginal area and drains into the coronary sinus. Together, these veins form the primary drainage pathway from the heart muscle to the right atrium. The other options refer to veins that don’t drain the myocardium (systemic veins like the inferior/superior vena cava or azygos), or to arteries, or to a statement about ischemia, none of which describe the venous drainage into the coronary sinus.