How many coronary arteries are there in the heart? There are three main coronary arteries that provide oxygen and nutrients to the myocardium (heart muscle). These include: the right coronary artery, left coronary artery and the circumflex artery.
There are multiple smaller coronary arteries that branch off from the left and right coronary artery and even the circumflex artery.
The myocardium itself actually gets 100% of its oxygen and nutrient supply from the coronary arteries and receives no oxygen or nutrients from the blood that passes through the ventricls of the heart.
The left side of the heart is fed by the left coronary artery and circumflex artery, which originate at the root of the aorta (before the aortic arch) during the diastolic phase (relaxation phase) of the heart. The left coronary artery originates from the left aortic sinus, while the right coronary artery originates from the right aortic sinus. These coronary arteries are relatively tiny compared to other arteries in the body, which is why they are prone to atherosclerosis (narrowing of the artery wall).
A very small proportion of people will have a fourth main artery (the posterior coronary artery), while an even rarer proportion of people will have only one single coronary artery that loops around the entire heart providing the only oxygenation supply.
If the atherosclerosis continues and the heart muscle is no longer able to acheive an homeostatic balance of oxygen used an oxygen received by in flowing blood, the heart muscle will start to die. This is when you will start to feel chest pain. If you want to learn more about chest pain, please visit my Chest Pain page.