Circumflex Coronary Artery

The Circumflex (Circ) coronary artery is a branch of the left main coronary artery. It travels in the left atrio-ventricular groove that separates the left atrium from the left ventricle. The Circ moves away from the LAD and wraps around to the back of the heart. The major branches that it gives off in the proximal or initial portion are known as obtuse marginal or OM coronary arteries. As the Circumflex Coronary Artery makes its way to the back to the posterior portion of the heart, it gives off one or more left postero-lateral (PL) branches.

In 85% of cases, the Circ terminates at this point and is known as a non-dominant left coronary artery system. In the other 15% of cases, a dominant Circ supplies the posterior descending artery, or PDA, which runs in the bottom of the heart within a groove that separates the left from the right ventricle.