Coronary artery anatomy, supply territories and dominance
THE CONTEXT
The coronary arteries arise from the aortic root and supply different regions of the cardiac chambers and interventricular septum.
Origins and left coronary branches
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The left main and right coronary arteries arise from the left and right aortic sinuses, respectively, superior to the aortic valve.
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Within 2.5 cm of its origin, the left main coronary artery divides into the left anterior descending artery (LAD) and the left circumflex artery (CX).
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The LAD runs in the anterior interventricular groove. Its septal perforators supply the anterior septum, and its branches supply the anterior, lateral and apical walls of the left ventricle.
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The CX runs posteriorly in the atrioventricular groove. Its marginal branches supply the lateral, posterior and inferior segments of the left ventricle.
Right coronary artery and coronary dominance
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The right coronary artery (RCA)* runs in the right atrioventricular groove and supplies the right atrium, right ventricle and inferoposterior aspects of the left ventricle.
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The posterior descending artery runs in the posterior interventricular groove and supplies the inferior part of the interventricular septum.
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The posterior descending artery arises from the RCA in approximately 90% of people, forming a dominant right system. In the remainder, it arises from the CX, forming a dominant left system.
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Coronary anatomy varies greatly between individuals, with many normal variants.