Subsinuosal interventricular branch

The subsinuosal interventricular branch of the right coronary artery arises as a terminal branch of the right coronary artery in species with right coronary dominance*.

It originates at the level of the coronary groove on the atrial (caudal) surface of the heart and enters the subsinuosal interventricular groove. From there, it runs toward the apex along this groove, which lies between the left and right ventricles on the atrial surfa

During its course, it gives off numerous collateral branches. These include ventricular branches that supply the caudal portions of both the right and left ventricular free walls, and septal branches that penetrate the interventricular septum. The septal branches anastomose with those arising from the paraconal interventricular branch, forming an intraseptal vascular network.

Near the apex, the subsinuosal interventricular branch may anastomose with terminal branches of the paraconal interventricular branch. The extent of this anastomosis varies depending on species and individual variation.

*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].