Coronary Artery Anatomy:  A Primer

I have been lecturing on heart disease to lay groups for over 40 years.  The insatiable desire for knowledge about heart disease by lay persons has been one of the highlights of my career.  These lectures are often fun with never ending questions.  I consider this a sign of a health conscious country.

One area rarely touched upon is the normal anatomy of the coronary arteries.  The anatomy is very important because it explains many of the conditions that develop.   First of all it is important to remember that ALL arteries arise from the Aorta.  The aorta is a long, elastic tube that runs upward from the heart, curves downward at the neck, runs the entire length of the body, splitting at the level of the umbilicus to send the major arteries to the legs.  The aorta expands with each heart beat and then maintains artery flow, by virtue of the elastic recoil, while the heart fills for the next beat.  The first branches of the aorta are the coronary arteries and they arise just beyond the Aortic valve.  As a result the coronary arteries get the first and the freshest blood when the heart contracts.  The coronary arteries spread out over the surface of the heart sending their branches downward into the heart muscle.  Thus the coronary arteries are very accessible to the surgeon for any operation on the arteries.  There are two coronary arteries, a right and left, but the left quickly divides into two major branches, so we really think in terms of 3 major arteries.   The names are the left anterior descending (LAD), the circumflex (CIRC) and the right coronary artery (RCA).  Each of these three arteries is usually about 15 centimeters in length.

The majority of plaques develop in the first 3-4 cm of the artery origin from the aorta.  As a result the artery beyond 4 cm is usually relatively free of plaques and is suitable for inserting a vein bypass graft from the aorta.  The vein graft bypasses the bad plaques and brings fresh blood to heart muscle starved for blood due to obstructing plaques upstream. 

Summary:  The coronary arteries are on the surface of the heart and are readily accessible to the surgeon.  There are 3 coronary arteries, each of about equal length, that carry fresh blood to the heart.  Plaques develop near the origin of the each coronary artery leaving the area beyond the plaques uninvolved and suitable for a bypass graft.