ABSTRACT
T he venous drainage system of the myocardium is divided in two parts (Fig. 3.1):A. The great (major) cardiac venous drainage system (GCVDS) extends over the surface of the ventricular and atrial myocardium. The distribution patterns of these veins are highly variable; however, the strongest veins drain the left ventricular myocardium and empty into the coronary sinus (cs). B. The small (minor) cardiac venous drainage system (SCVDS) is found in a suben docardial location in the innermost myocardial layers of the cardiac walls.These very short cardiac veins have an ostial diameter of less than 1 mm; in the adult they repre sent the primitive supply and drainage system of the spongeous myocardium that was carried out by endocardialy-sinusoidal vessels usually connected to the next chamber in the embryo.
