Coronary arteries

The left main and right coronary arteries arise from the coronary ostia, small orifices located just above the aortic valve cusps. The right coronary artery fills the groove between the atria and ventricles, giving rise to the acute marginal artery and ending as the posterior descending artery. The right coronary artery supplies blood to the right atrium, the right ventricle, and the inferior wall of the left ventricle. This artery also supplies blood to the SA node in about 50% of the population and to the AV node in 90% of the population. The posterior descending artery supplies the posterior wall of the left ventricle in 80% to 90% of the population. Coronary arteries The left main coronary artery varies in length from a few millimeters to a few centimeters. It splits into two major branches, the left anterior descending artery (also known as the interventricular artery) and the left circumflex artery. The left anterior descending artery runs down the anterior surface of the heart toward the apex. This artery and its branches- the diagonal arteries and the septal perforators - supply blood to the anterior wall of the left ventricle, the anterior interventricular septum, the bundle of His, the right bundle branch, and the anterior fasciculus of the left bundle branch. Coronary arteries The circumflex artery circles the left ventricle, ending on its posterior surface. The obtuse marginal artery arises from the circumflex artery. The circumflex artery provides oxygenated blood to the lateral wall of the left ventricle, the left atrium, the posterior wall of the left ventricle in 10% of the population, and the posterior fasciculus of the left bundle branch. In about 50% of the population, it supplies the SA node; in about 10% of the population, the AV node. P.8Vessels that supply the heart The coronary circulation involves the arterial system of blood vessels, which supplies oxygenated blood to the heart, and the venous system, which removes oxygen-depleted blood from the heart. In most of the population, the right coronary artery is the dominant vessel, meaning that the right coronary artery supplies the posterior wall via the posterior descending artery. This system is described as right coronary dominance or a dominant right coronary artery. Likewise, patients in whom the left coronary artery supplies the posterior wall via the posterior descending artery, the terms left coronary dominance or a dominant left coronary artery are used. When two or more arteries supply the same region, they usually connect through anastomoses, junctions that provide alternative routes of blood flow. This network of smaller arteries, called collateral circulation, provides blood to capillaries that directly feed the heart muscle. Collateral P.9circulation becomes so strong in many patients that even if major coronary arteries become narrowed with plaque, collateral circulation can continue to supply blood to the heart.