What is meant by coronary dominance?

The posterior descending artery supplies the diaphragmatic surface of the left ventricle and the posterior ventricular septum. If the posterior descending artery is a branch of the right coronary artery, as it is in 85% of patients, the system is right dominant. If the posterior descending artery is a branch of the left coronary artery, the system is left dominant. If the posterior descending artery is supplied by both the right and the left coronary arteries, the system is balanced or codominant.