The left coronary artery branches into which two arteries?

• A. Anterior descending artery and circumflex artery
• B. Right coronary artery and posterior descending artery
• C. Marginal artery and posterior descending artery
• D. Circumflex artery and posterior descending artery

Answer: (A)

The left coronary artery splits into two main branches: the left anterior descending (anterior interventricular) artery and the left circumflex artery. The LAD runs down the anterior interventricular groove toward the apex, supplying the anterior wall of the left ventricle and most of the interventricular septum. The circumflex artery travels in the left atrioventricular groove and sends obtuse marginal branches to the lateral/posterior walls. The posterior descending artery isn’t a direct branch of the left coronary in all hearts—it can arise from the right coronary artery or from the circumflex in left-dominant systems. So, the two primary branches of the left coronary artery are the anterior descending artery and the circumflex artery.