What is the usual origin of the SA and AV nodal arteries?

What is the usual origin of the SA and AV nodal arteries?

• A. Left coronary artery
• B. Aorta
• C. Right coronary artery
• D. Brachiocephalic trunk

Answer: (C)

The SA nodal artery and the AV nodal artery most commonly arise from the right coronary artery. In the usual right-dominant hearts, the RCA gives off a nodal branch to the SA node as it travels in the right atrium, and the AV nodal artery typically comes from the RCA at the crux of the heart, often via the posterior interventricular pathway. Because this right-sided supply is by far the most common pattern, the usual origin for both nodal arteries is the right coronary artery. In less common left-dominant cases, these nodal vessels can originate from the left coronary system, but that’s not the typical scenario. The aorta is the source of the coronary arteries themselves, not the nodal arteries directly, and the brachiocephalic trunk has no direct role here.

The SA nodal artery and the AV nodal artery most commonly arise from the right coronary artery. In the usual right-dominant hearts, the RCA gives off a nodal branch to the SA node as it travels in the right atrium, and the AV nodal artery typically comes from the RCA at the crux of the heart, often via the posterior interventricular pathway. Because this right-sided supply is by far the most common pattern, the usual origin for both nodal arteries is the right coronary artery. In less common left-dominant cases, these nodal vessels can originate from the left coronary system, but that’s not the typical scenario. The aorta is the source of the coronary arteries themselves, not the nodal arteries directly, and the brachiocephalic trunk has no direct role here.