The heart receives its own supply of blood from the coronary arteries. Two major coronary arteries branch off from the aorta near the point where the aorta and the left ventricle meet. These arteries and their branches supply all parts of the heart muscle with blood.
Left Main Coronary Artery (also called the left main trunk)
The left main coronary artery branches into:
- Circumflex artery
- Left Anterior Descending artery (LAD)
The left coronary arteries supply:
- Circumflex artery - supplies blood to the left atrium, side and back of the left ventricle
- Left Anterior Descending artery (LAD) - supplies the front and bottom of the left ventricle and the front of the septum
Right Coronary Artery (RCA)
The right coronary artery branches into:
- Right marginal artery
- Posterior descending artery
The right coronary artery supplies:
- right atrium
- right ventricle
- bottom portion of both ventricles and back of the septum
The main portion of the right coronary artery provides blood to the right side of the heart, which pumps blood to the lungs. The rest of the right coronary artery and its main branch, the posterior descending artery, together with the branches of the circumflex artery, run across the surface of the heart's underside, supplying the bottom portion of the left ventricle and back of the septum.
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.