What Are The Coronary Arteries?

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Like all organs, your heart is made of tissue and requires a supply of oxygen and nutrients. Although its chambers are full of blood, the heart receives no nourishment from this blood. The heart receives its own supply of blood from a network of arteries, called the coronary arteries.

Two major coronary arteries branch off from the aorta near the point where the aorta and the left ventricle meet:

  • the right coronary artery (RCA) which supplies the right atrium and right ventricle. It branches into the posterior descending artery which supplies the bottom portion of the left ventricle and back of the septum.

  • the left main coronary artery, which branches into:

  • the circumflex artery, which supplies blood to the left atrium, side and back of the left ventricle


  • the left anterior descending artery (LAD), which supplies the front and bottom of the left ventricle and the front of the septum

These arteries and their branches supply all parts of the heart muscle with blood

What is collateral circulation?

Collateral circulation is a network of tiny blood vessels, and, under normal conditions, not open. When the coronary arteries narrow to the point that blood flow to the heart muscle is limited (coronary artery disease), collateral vessels may enlarge and become active. This allows blood to flow around the blocked artery to another artery nearby or to the same artery past the blockage, protecting the heart tissue from injury.