left coronary artery left coronary artery the left coronary artery (lca) (also known as the left main coronary artery, or left main stem coronary artery) is a coronary artery that arises from the aorta above the left cusp of the aortic valve, and supplies blood to the left side of the heart muscle. the left coronary artery typically runs for 10-25 mm, then bifurcates into the left anterior descending artery, and the left circumflex artery. left coronary arteryheart viewed from above, atria removed, base of ventricles exposed. left coronary artery visible at left.heart viewed from the front. coronary arteries (labeled in red text) and other major landmarks (in blue text). left coronary artery is at upper right in the image.detailssourceascending aortabranchesanterior interventricular circumflex (ramus intermedius)identifierslatinarteria coronaria sinistracode: lat promoted to code: la ta98a12.2.03.201ta24142fma50040anatomical terminology the part that is between the aorta and the bifurcation only is known as the left main artery (lm), while the term "lca" might refer to just the left main, or to the left main and all its eventual branches. structure variation sometimes, an additional artery arises at the bifurcation of the left main artery, forming a trifurcation; this extra artery is called the ramus or intermediate artery. a "first septal branch" is sometimes described. additional images left coronary artery cardiac vessels the aortic arch and its branches diagram of the arch human heart with coronary arteries heart left lateral coronaries diagram diagram of a myocardial infarction a coronary angiogram that shows the lmca, lad, and lcx autopsy specimen showing the coronary ostia and proximal segments of the coronary arteries. compare with gray's anatomy drawing above. left coronary artery left coronary artery. plastination technique left coronary artery. plastination technique