Final answer:
Coronary dominance is based on whether the right or left coronary artery supplies the posterior descending artery (PDA). The right coronary artery commonly supplies the PDA in right-dominant individuals, while the PDA may be supplied by the circumflex artery in left-dominant individuals.
Step-by-step explanation:
Coronary dominance is determined by the coronary artery that supplies the posterior descending artery (PDA), which in turn supplies blood to the AV node. The two main coronary arteries involved in this are the right coronary artery and the left coronary artery. The former runs along the coronary sulcus, giving rise to the marginal arteries that supply the right ventricle, and the posterior interventricular artery (PDA), which supplies the interventricular septum and both ventricles.
This artery is usually the one responsible for supplying the PDA in individuals with right-dominant coronary circulation. On the other hand, the circumflex artery, a branch of the left coronary artery, can give rise to the PDA in left-dominant or co-dominant circulations. Thus, coronary dominance can be right-dominant, left-dominant, or co-dominant, depending on which coronary artery supplies the PDA. Anastomoses between branches of these arteries exist, providing collateral circulation and ensuring myocardial blood supply even in the case of a partial blockage.