From the coronary arteries and their major branches, many small arteries run into the muscular walls of the heart, and these small arteries give rise to rich capillary networks that bathe the cardiac muscle cells with blood.
The left circumflex coronary artery runs to the left (at a right angle to the LAD ) along the groove between the left atrium and the left ventricle. The left circumflex coronary artery supplies blood to the side or lateral wall of the left ventricle. However, people vary in the way the blood supply to the heart is divided between the right and left coronary arteries. There is not much overlap between the territories of the major branches of the coronary arteries. The choice of donor sites will depend on the number of grafts to be performed, and whether saphenous veins are available and suitable. There may be visible varicosities, or they may have been stripped or used in previous surgery. The right coronary artery branches behind the heart and gives rise to the posterior descending coronary artery, which parallels the LAD in front. The right coronary artery supplies the bottom and backside of the heart, and in most people, it supplies blood to the right ventricle and to the sinus and AV nodes of the hearts electrical conduction system.