The coronary arteries arise from the coronary sinuses immediately distal (superior) to the aortic valve and supply the myocardium of the heart with oxygenated blood. The arteries branch to encircle the heart covering its surface with a lacy network, perhaps resembling a slightly crooked crown.
The typical configuration consists of two coronary arteries, a left coronary artery (LMCA) and a right coronary artery (RCA), arising from the left posterior and right anterior aortic or coronary sinuses respectively, in the proximal ascending aorta. These are the only two branches of the ascending aorta.
The right coronary artery courses in the right atrioventricular groove to the inferior surface of the heart, whereupon it turns anteriorly at the crux as the posterior descending artery (PDA) in right dominant circulation.
The left coronary artery has a short common stem (and is hence often referred to as the left main coronary artery), that bifurcates into the left circumflex artery (LCx), which courses over the left atrioventricular groove, and the left anterior descending artery (LAD), which passes towards the apex in the anterior interventricular groove. Occasionally there is a trifurcation (in ~15%), with the third branch, the ramus intermedius, arising between the LAD and LCx. In left dominant hearts, the LCx supplies the posterior descending artery (PDA).
- left coronary artery
- right coronary artery (RCA)
Most hearts are right dominant (60%) where the PDA is supplied by the RCA. However, up to 20% of hearts may be left dominant, where the PDA is supplied by the LAD or LCx, or codominant, where a single or duplicated PDA is supplied by branches of both the RCA and LAD/LCx (20%).
For a more in-depth discussion of coronary dominance, see the article coronary arterial dominance.
Although there are variations (see main article: congenital coronary artery anomalies), the anatomy is relatively consistent.
History and etymology
Coronary comes from the Latin "coronarius", meaning belonging to a crown or wreath.