*The coronary arteries and the veins that drain into the coronary sinus. The posterior interventricular branch (PIV), although usually a branch of the right coronary artery (RC), may arise from the circumflex branch (C) of the left coronary artery (inset). In B, the left marginal vein can be seen ascending to join the great cardiac vein. The posterior vein of the left ventricle ascends and the oblique vein of the left atrium descends to end in the coronary sinus.
*AIV, anterior interventricular branch; C, circumflex branch; GC, great cardiac vein; LC, left coronary artery; MC, middle cardiac vein; PIV, posterior interventricular branch; Re, right coronary artery; S.-A, branch to sinuatrial node; SC, small cardiac vein.