The left coronary artery is a one of the two main blood vessels that supply the heart with oxygenated blood. It is larger than the right coronary, with more side branches, carrying more blood volume. Supplying a large area of the myocardium, it is in one of its branches where most of the heart coronary occlusion occurs.
The left coronary artery originates from the left sinus of Valsalva (left aortic sinus), which is just above the left cusp of the aortic valve. It runs to the left, behind the root of the pulmonary trunk and then between the pulmonary trunk and the auricle of the left atrium. When it is about to reach the left half of the atrioventricular groove, the left coronary artery divides into two important branches; the anterior interventricular and the circumflex branch.
The anterior interventricular branch (also called left anterior descending artery) runs all the way down along the anterior interventricular groove on anterior side of heart, reaching the apex of heart. Along the way, it sends secondary side branches, such as the diagonal branch. Meanwhile, the circumflex artery turns left, gives off the left marginal branch and keeps traveling sideways, winding around the heart in the atrioventricular groove to the posterior side of this organ where it descends across its posterior surface.
Below, image of anterior aspect of heart, showing the left coronary artery and its branches.
