ABSTRACT
The left main coronary artery arises from the left posterior aortic sinus. The main left coronary artery bifurcates, beneath the left atrial appendix, into the left anterior descending (LAD) and the circumflex arteries. The LAD artery provides two main groups of branches: first, the septal branches, which supply the anterior two-thirds of the septum; and, second, the diagonal branches which lie on the lateral aspect of the left ventricle. The right coronary artery (RCA) arises from the anterior aortic sinus, passes forwards and then downwards, in the right atrioventricular groove and continues around the margin of the heart towards the crux, a point where the atrioventricular groove and the posterior interventricular groove meet. In the majority of individuals the RCA is the dominant vessel and continues forwards from the crux along the posterior interventricular groove to become the posterior descending artery.
