The artery primarily supplying the posterior wall of the left ventricle is a branch of the left coronary artery.

• A. Left Anterior Descending Artery
• B. Left Circumflex Artery
• C. Right Coronary Artery
• D. Right Marginal Artery

Answer: (B)

Understanding coronary artery distribution and dominance helps here. The left coronary artery splits into the left anterior descending and the left circumflex. The posterior wall of the left ventricle is supplied by a branch that commonly comes from the left circumflex—the posterior left ventricular branch—especially in left-dominant circulation. In contrast, the right coronary artery typically feeds the posterior region in right-dominant hearts via the posterior descending artery. The left anterior descending supplies the anterior wall and interventricular septum, while branches of the right coronary artery and its marginal branches mainly supply the right heart. Therefore, when the posterior wall’s supply is described as a branch of the left coronary artery, the left circumflex is the best fit.