Which artery determines dominant blood supply to the posterior heart when it supplies the posterior surface and interventricular septum?

Which artery determines dominant blood supply to the posterior heart when it supplies the posterior surface and interventricular septum?

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

Answer: (A)

Dominance of the coronary circulation is defined by which artery gives rise to the posterior descending artery, which supplies the posterior surface of the heart and the interventricular septum. In most people, that artery is the right coronary artery, so it determines the dominant blood supply to the posterior heart. (In a smaller number of individuals, the left coronary system—via the left circumflex—provides the posterior descending artery, leading to left dominance; some people have a codominant pattern with contributions from both.) Thus, when the artery that reaches the posterior wall and the IV septum comes from the right coronary artery, that artery sets the dominant supply.