The term [coronary dominance] is the answer to the following question: From which coronary artery does the posterior interventriclular artery (PDA) arise?
In most of the human species the PDA arises from the right coronary artery, (see acompanying image), therefore most humans (70%) are right dominant. The rest are either left dominant (10%) or have balanced dominance (20%). These statistics have significant variation in different studies.
In the case of balanced dominance, there is either a double posterior interventricular artery, where one is a branch of the right coronary artery and the other a branch of the left coronary artery, or a single PDA receiving blood supply from both coranary arteries.
|Coronary dominance is important because the interventricular septum receives blood supply from the PDA in its posterior 1/3rd. If the heart is left dominant, all the blood supply of the interventricular septum is dependant on the left coronary artery. In this case, blockage of the left coronary artery can be catastrophic!
There can be interesting anatomical variations in the coronary arteries of the heart. For a detail on these anatomical variations, click here. Heart and coronary artery anatomy is one of the many lecture topics presented by CAA, Inc