The right coronary artery originates form the right aortic valvular cusp, its, SA nodal branch supplies the SA node and AV nodal branch supply the AV node.
The right coronary artery further branches off into the right marginal artery and posterior descending artery supplying the right ventricular myocardium and posterior two-thirds of the inter-ventricular septum. The left coronary artery originates from the left aortic valvular cusp. The left main coronary artery bifurcates approximately 1.5 to 2.5 cm in to the left anterior descending and the circumflex arteries. The left anterior descending artery extends down the inter- ventricular groove and supplies the anterior left ventricular wall, anterior third of the ventricular septum and frequently the apex. The circumflex artery travels around the left ventricle along the atrio-ventricular groove to the posterior left ventricle. It supplies the lateral and posterior myocardi& and sometimes the AV node.