Which coronary arteries primarily supply the interatrial septum?

The right coronary artery primarily supplies the interatrial septum in most individuals, particularly through its branches. This is significant because the interatrial septum plays a crucial role in separating the left and right atria, and maintaining its blood supply is vital for normal cardiac function.

In the typical anatomy of coronary circulation, the right coronary artery gives rise to the posterior descending artery (PDA), which often supplies blood to the inferior wall of the heart and also contributes branches that supply the interatrial septum. This is particularly relevant for the right-dominant coronary circulation, which is present in the majority of people.

The left coronary artery, though it supplies other critical regions of the heart, does not primarily provide blood to the interatrial septum. While the circumflex artery (a branch of the left coronary artery) may contribute indirectly through other branches, its primary supply focus is not on the interatrial septum. A combined supply from both coronary arteries is less common and does not represent the typical anatomy. Therefore, identifying the right coronary artery as the primary supplier is essential for understanding coronary physiology and pathology related to the atrial septum.