Which artery is the major supplier of oxygenated blood to the heart?

• A. Right coronary artery
• B. Left anterior descending artery
• C. Circumflex artery
• D. Left coronary artery

Answer: (D)

This question tests which coronary artery primarily supplies oxygenated blood to the heart muscle. The left coronary artery, which arises from the aorta, is the main source. It quickly divides into two major branches—the left anterior descending and circumflex arteries—that feed the left ventricle and the interventricular septum. The left ventricle is the heart’s thickest, most active chamber with the highest oxygen demand, so supplying its walls accounts for the majority of myocardial blood flow. The right coronary artery mainly serves the right side of the heart and portions of the left ventricle, but does not provide the bulk of the myocardium’s blood supply.