What are the 3 main arteries of the heart?

The Three Main Coronary Arteries

The heart is supplied by three main coronary arteries: the Left Anterior Descending (LAD) artery, the Left Circumflex (LCx) artery, and the Right Coronary Artery (RCA). 1

Anatomical Organization

The coronary arterial system originates from the aortic root and branches into these three major vessels that supply oxygenated blood to the myocardium 1:

Left Main Coronary Artery and Its Branches

• The left main coronary artery (LMCA) arises from the left coronary ostium and bifurcates (or occasionally trifurcates) into the LAD and LCx arteries 2
• The left main ostium includes the first 3 mm of the artery, with the body extending from the ostium to the bifurcation 2, 1

The Three Main Epicardial Vessels

1. Left Anterior Descending (LAD) Artery

   • Courses down the anterior interventricular groove 2
   • Gives off diagonal branches that supply the anterolateral wall of the left ventricle 2
   • Provides septal perforator branches to the interventricular septum 2

2. Left Circumflex (LCx) Artery

   • Travels in the left atrioventricular groove 2
   • Gives off obtuse marginal branches that supply the lateral wall of the left ventricle 2
   • In left-dominant systems, may give rise to the posterior descending artery 2

3. Right Coronary Artery (RCA)

   • Supplies the right atrium, right ventricle, sinoatrial node, and posterior portion of the interventricular septum 3, 1
   • In right-dominant circulation (approximately 90% of people), gives rise to the posterior descending artery (PDA) and posterolateral branches 3
   • Supplies the inferior wall of the left ventricle in right-dominant systems 3, 1

Clinical Significance

• Coronary dominance is determined by which artery (RCA or LCx) supplies the posterior descending artery and left posterior ventricular branch 2
• These three vessels and their branches are the primary targets for assessment in coronary angiography and CT angiography 2
• Vessels of 1.5 to 2 mm in diameter can be assessed for atherosclerotic narrowing using modern imaging techniques 2