Left coronary artery

The left coronary artery (LCA, Latin: arteria coronaria sinistra) is a branch of the ascending aorta. It is one of the main blood vessels that supplies he heart with oxygenated blood. The left coronary artery supplies the following heart parts: left atrium, most of the left ventricle, and the majority of the interventricular septum.

The LCA arises from the left semilunar cusp (sinus of Valsalva). The artery passes between the left atrial (auricular) appendage and the pulmonary trunk. As it enters the left half of the sternocostal atrioventricular groove, the LCA turns left toward the obtuse margin of the heart. The initial segment of the artery ends at its first bifurcation, where it divides into the anterior interventricular artery and the left circumflex artery. Before its bifurcation, the initial portion of the left coronary artery usually has no branches arising from it. However, sometimes it gives off a small sinoatrial node artery and an atrial ramus.

Branches of left coronary artery

Anterior interventricular artery

The anterior interventricular artery (also known as the left anterior descending artery) arises from the left coronary artery to supply the anterior and left side of the heart. The artery travels within the anterior interventricular groove inferolaterally. It gives off several branches, including:

  • Left conus artery - supplies the outflow tract of the right ventricle and a large part of the anterior free wall of the right ventricle;
  • Anterior ventricular arteries (as many as nine of them) - supplies the left ventricle;
  • Posterior ventricular branch - supplies the left ventricle;
  • Interventricular septal arteries (anterior, inferior) - to the interventricular septum of the heart.

The anterior interventricular artery may terminate at the cardiac apex. Still, more often, it continues onto the diaphragmatic surface of the heart and meets the terminal branches of the posterior descending artery - a branch of the right coronary artery.

Left circumflex artery

The left circumflex artery is a branch of the LCA that supplies most of the left atrium. After arising, this artery takes a left course in the atrioventricular groove while being overlapped by the left atrial (auricular) appendage. Further, the left circumflex artery crosses over the obtuse border of the heart. The artery may give rise to atrial branches (posterior, lateral, and anterior divisions) that supply the left atrium. Other branches of the left circumflex artery include:

  • Kugel`s anastomotic artery - provides anastomotic pathways between the right and left coronary arteries;
  • Left marginal branch - supplies the diaphragmatic part of the left ventricle;
  • Anterior and posterior ventricular arteries - supply the left ventricle.