Coronary Arteries

The right and left coronary arteries supply blood to your heart. They’re the first branches off the aorta, which is the main artery in your body. These arteries and their branches supply all parts of the heart muscle with blood.


What are coronary arteries?

The coronary arteries are major blood vessels in your body, supplying blood to your heart. They make it possible for your heart to beat and pump blood throughout your body. You have a right coronary artery (RCA) and a left main coronary artery (LMCA). Each contains smaller branches that go deep inside your heart muscle.


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What is the purpose of the coronary artery?

The function of the coronary arteries and their branches is to supply your heart with blood. Your heart muscles need the oxygen and nutrients in blood so they can pump blood through your heart and the rest of your body.


Where are the coronary arteries located?

Your coronary arteries are around and inside your heart muscle. They branch off your aorta, which is the main artery in your body. They start at the aortic root, which is the first part of your aorta that emerges from the left ventricle of your heart. The left ventricle is where oxygenated blood leaves your heart and starts its journey through your body. The coronary artery branches are the first of many branches off your aorta.

Coronary artery structure

There are two coronary arteries, each containing several branches:

  • Right coronary artery (RCA): The RCA supplies blood to your right atrium and right ventricle (where deoxygenated blood goes before heading to the lungs). Its branches supply the sinoatrial (SA) and atrioventricular (AV) nodes. These nodes send electrical signals through your heart, so the heart muscles know when to contract. Branches of the RCA also deliver blood to one-third of your interventricular septum, which is the wall between your heart’s two lower chambers.
  • Left main coronary artery (LMCA): The LMCA supplies blood to your left atrium and left ventricle. This is where oxygenated blood arrives from your lungs before your heart pumps it out to the rest of your body. Its branches supply blood to the other two-thirds of your interventricular septum.

Is the structure of the coronary artery always the same?

It’s important to note that sometimes the structure of the coronary artery branches varies from person to person. Some examples are:

  • Coronary arteries are usually surrounded by a layer of fat but in some people the arteries are within the heart muscle itself.
  • Blood supply to the SA and AV nodes comes from the LCMA, not the RCA, in about 10% of people.
  • Sometimes a single coronary artery arises from the aorta, then divides into right and left branches.

Most of these variations aren’t harmful and don’t produce symptoms. But in rare cases (less than 1% of people) coronary artery abnormalities can lead to serious problems or even death.


How big are the coronary arteries?

The main coronary arteries are usually between 3 and 4 millimeters in diameter. That’s a little smaller than the width of a drinking straw. The sizes of the arteries vary slightly according to your sex, body weight and even ethnicity.

What are the coronary arteries made of?

The walls of all arteries, including the coronary arteries, contain three layers:

  • Tunica intima: The inner layer touches your blood and keeps it flowing smoothly through your arteries.
  • Media: The middle layer is elastic, so it expands and contracts to maintain the right blood pressure in your arteries.
  • Adventitia: The outer layer contains tiny vessels that deliver oxygen and nutrients from your blood to the cells in your heart.


Conditions and Disorders

What conditions and disorders affect the coronary arteries?

Coronary artery disease (CAD) is the most common condition that affects your coronary arteries. CAD is often the result of atherosclerosis, which is plaque buildup inside your arteries. Clogged arteries prevent blood from getting to your heart, which can lead to a heart attack.

Acute coronary syndrome is a condition that results in a sudden loss of blood flow to your heart through your coronary arteries. A heart attack is a type of acute coronary syndrome. Like CAD, these conditions are also a result of atherosclerosis.

Less common conditions that affect your coronary arteries include:

  • Aneurysms: Bulges in a blood vessel wall.
  • Congenital (present at birth) abnormalities in your arteries.
  • Coronary spasms: Sudden tightening of the muscles in your arteries. When these muscles tighten or spasm, your arteries are temporarily blocked. This can lead to chest pain called Prinzmetal angina.


How can I keep my coronary arteries healthy?

Keep your heart and coronary arteries healthy by:

Additional Common Questions

When should I call my doctor?

Call 911 right away if you experience any of the following symptoms, which could be signs of a heart attack:

  • Chest pain.
  • Cold sweat.
  • Jaw, neck, back, arm or shoulder pain.
  • Shortness of breath.
  • Weakness or light-headedness.

A note from Cleveland Clinic

Your coronary arteries carry blood to your heart. They supply your heart muscles with the oxygen and nutrients they need to pump blood through your body. Coronary artery disease (CAD) occurs if these arteries clog and don’t deliver enough blood to your heart. You can reduce your risk of CAD or a heart attack by exercising, eating a healthy diet and not smoking or using tobacco products.

Medically Reviewed

Last reviewed on 05/09/2022.

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