[TA] a vessel of variable origin, most commonly a branch of the circumflex artery, coursing posteriorly through the base of the interatrial septum toward the crux of the heart, anastomosing with coronary artery branches supplying the atrioventricular node, the atrioventricular bundle (bundle of His), and the upper posterior walls of the left ventricle. SYN: ramus atrialis anastomoticus ramus circumflexus arteriae coronariae sinistrae [TA], arteria anastomotica auricularis magna, Kugel anastomotic artery.