Circumflex artery

The circumflex (left circumflex artery, LCX) branch of the left coronary artery follows the coronary sulcus around the left margin of the heart. On the posterior surface of the heart, it reaches nearly as far as the posterior interventricular sulcus.

The circumflex artery gives rise to one or more left marginal arteries (also called obtuse marginal branches) as it curves toward the posterior surface of the heart. In 15% of people (with Left Dominant hearts), it continues as the posterior interventricular artery, which descends in the posterior interventricular sulcus. (In the other 85% of people, the posterior interventricular artery comes from the right coronary artery).

The circumflex artery supplies the posterolateral left ventricle and the anterolateral papillary muscle. It also supplies the sinoatrial node in 38% of people. It supplies 15-25% of the left ventricle in Right Dominant hearts. In Left Dominant hearts, the circumflex artery supplies 40-50% of the left ventricle.