|MadSci Network: General Biology|
I assume your question is referring to the coronary arteries. There are two main coronary arteries which branch from the aorta, the Left Main Coronary Artery (LMCA) and the Right Coronary Artery (RCA). You can see these in the image below or you can go to: http://www.heartpoint.com/coronart.html. The LMCA ranges from 1 to 15 millimeters in length. One millimeter is approximately the thickness of a dime. The LMCA divides into the Left Anterior Descending (the "widow's artery") and the Left Circumflex Artery. Both of these branches together supply a considerable amount of the myocardium with blood. The Right Coronary Artery (RCA) is longer than the LMCA but smaller in diameter and supplies a smaller amount of myocardium with blood.
In summary, the LMCA is shorter but larger in diameter and more critical then the RCA.
I hope this answers your question.
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