Which artery primarily supplies the right atrium?

The right atrium is primarily supplied by the right coronary artery, which is a branch of the aorta. This artery plays a crucial role in delivering oxygenated blood to the heart muscle of the right atrium and also provides supply to parts of the right ventricle and the conduction system of the heart, including the sinoatrial (SA) node in most individuals. The dominant coronary system varies among individuals, but in about 70% of people, the right coronary artery is the one that supplies the SA node, which is essential for initiating the heartbeat.

This anatomical relationship underscores the importance of the right coronary artery in maintaining proper atrial function, as it ensures adequate blood flow to the atrial walls. In contrast, other arteries listed do not significantly contribute to the blood supply of the right atrium; for instance, the left coronary artery primarily serves the left atrium and the left ventricle, while the anterior interventricular artery and the posterior descending artery are primarily involved with other regions of the heart.