Right coronary artery

The right coronary artery arises from the right aortic sinus of the ascending aorta. It passes between the right auricle and the pulmonary trunk to reach the coronary groove.

From its origin, it courses within the coronary groove on the right (auricular) aspect of the heart, running caudally toward the atrial surface. It follows the groove between the right atrium and the right ventricle and then curves around the right border to reach the caudal aspect of the heart.

Along its course, the right coronary artery gives off several collateral branches. These include atrial branches supplying the right atrium, ventricular branches supplying the right ventricular free wall, and the conal branch to the conus arteriosus. In many species, it also gives rise to the sinoatrial nodal branch. In right coronary dominance*, it continues as the subsinuosal interventricular branch.

The right coronary artery supplies most of the right atrium, the majority of the right ventricle, part of the left ventricle (particularly its caudal portion), and components of the cardiac conduction system. Its extent and distribution vary among domestic animals depending on the pattern of coronary dominance.

*The coronary dominance of a heart refers to the coronary artery (LCA or RCA) that perfuses the majority of the myocardial tissue and variable methods to determine this have been reported including which coronary artery supplies the subsinuosal interventricular branch, which coronary artery extends beyond the crux of the heart, the relative lengths and number of branches of the LCA or RCA, and the origination and layout of the arteries at the apex of the heart. The dog normally displays a left dominant coronary circulation , the cat is less studied but appears variable with a majority of cases indicating right coronary dominance, the rabbit is variable with predominately left coronary dominance, and the goat, swine, horse and donkey, cow, camelids, and 90% of humans are right dominant. In the mouse and rabbit, the subsinuosal interventricular branch is reported to be absent [1].