What’s the Largest Blood Vessel In The Body?

Human heart with vessels, bronchial tree and cut rib cage. On white background. 3d rendering.
© Matis75/Shutterstock.com

Written by Janet F. Murray

Published: September 6, 2022

Share on:


What comes to mind when you think of the largest blood vessel in the body? The aorta? While it is true that the aorta is the largest artery in the body, did you know that the most vital vein is the vena cava? In this blog post, we’ll take a closer look at both these primary blood vessels and other vital veins in the body. Take a journey with us into the very essence of human anatomy as we explore some key characteristics of the aorta and other blood vessels.


The aorta is the largest blood vessel in the body. It carries oxygen rich blood to the body, without which we would die.


What Are Blood Vessels?

Blood vessels are the tubes that carry blood around the body. They are present in the form of arteries, veins, and capillaries. The arteries specialize in carrying blood that is rich in oxygen from the heart to the rest of the body. The veins transport blood that is full of carbon dioxide from the body back to the heart. Finally, the capillaries are tiny blood vessels that connect the arteries and veins. Blood vessels are vital because they transport oxygen and nutrients to the body’s cells. Additionally, they remove carbon dioxide and other waste products. Without blood vessels, the cells of the body would not be able to function properly.

What Is the Aorta?

The aorta is a big vessel that travels from the heart to the rest of the body. It is the body’s primary artery and is about as thick as a garden hose. The blood it transports is also filled with oxygen. This significant blood vessel begins at the top of the heart, just below the left side of the breastbone. It runs down the left side of the chest and abdomen. Eventually, it splits into smaller arteries that supply blood to the legs, pelvis, and other organs.

The aorta is necessary for life because it carries blood full of oxygen to the body’s organs and tissues. Without it, the body would quickly die. Unfortunately, the aorta is vulnerable to several problems, such as atherosclerosis (hardening of the arteries), aneurysms (bulges in the artery wall), and dissection (tearing of the artery). These conditions can cost you your life and require immediate medical attention.

How Many Parts Are There to the Aorta?

As the largest artery in the human body, the aorta begins at the heart. It extends down through the chest and abdomen and has four sections. These sections are the ascending aorta, aortic arch, descending or thoracic aorta, and abdominal aorta. This system ends at the same level as the L4 vertebrae, splitting into the left and right common iliac arteries. Each section has a different role and is subject to various diseases.

largest blood vessel in the body

The aorta has four parts; the ascending aorta, aortic arch, descending or thoracic aorta, and abdominal aorta.


Ascending Aorta

The thoracic aorta runs through the chest. It begins at the aortic arch and extends down to the diaphragm. The thoracic aorta has vessels that supply blood to the chest’s heart, lungs, and other structures.

The first part of the aorta is the ascending aorta. It begins at the aortic valve between the left ventricle (the heart’s main pumping chamber) and the aorta. The ascending aorta measures about 2 inches long. It runs alongside the pulmonary trunk (the vessel that carries blood to the lungs) in the pericardial sheath (a sac that lies around and protects the heart).

The left and right aortic sinuses or branches are dilations, or widened areas, in the ascending aorta. They are at the level of the aortic valve. The left and right aortic sinuses give rise to the left and right coronary arteries, which supply blood that is rich in oxygen to the heart muscle.

Aortic Arch

The aortic arch is a vital structure in the human body. It lies at the base of the heart and gives rise to the four principal arteries that transfer blood to the head, arms, hands, legs, and feet. The aortic arch has three primary branches: the brachiocephalic trunk, the left common carotid artery, and the left subclavian artery. Each of these arteries serves a vital function in sending blood to the brain, neck, and arms.

Thoracic Aorta

The thoracic aorta is a branch extending from the heart to the diaphragm. It is made up of the bronchial, mediastinal, and oesophageal arteries. The thoracic aorta also has numerous smaller parts. These parts are the pericardial, superior phrenic, and intercostal and subcostal arteries. They supply blood to the bronchial and peribronchial tissue. Additionally, they transfer blood to the lymph glands, esophagus, pericardium, diaphragm, and flat stomach wall muscles.

Abdominal Aorta

The thoracic aorta continues as the abdominal aorta. It extends from the diaphragm to the fourth lumbar vertebra level, dividing into the right and left common iliac arteries. It is the largest artery in the abdominal cavity, supplying oxygenated blood to the abdomen, pelvic organs, and legs. In addition, numerous key blood vessels, nerves, and muscles lie around the abdominal aorta.

The arteries branching out from the abdominal aorta are:

  • Inferior phrenic arteries
  • Coeliac artery
  • Superior mesenteric artery
  • Middle suprarenal arteries
  • Renal arteries
  • Gonadal arteries
  • Inferior mesenteric artery
  • Median sacral artery
  • Lumbar arteries

These branching arteries supply the digestive organs, adrenal glands, kidneys, and other abdominal structures with oxygenated blood.

What Are the Two Biggest Veins in the Human Body?

largest blood vessel in the body

The vena cava are the largest veins in the body, splitting into the superior vena cava and the inferior vena cava.


Most people know that the veins in our body are responsible for carrying blood back to the heart. And by now, the vital importance of the aorta has been established. But did you know that there are two large veins in the body? These are the superior vena cava and the inferior vena cava veins.

The superior vena cava is a large vein that carries blood from the upper body to the heart. This vein is located in the chest and is about 8 inches long. The inferior vena cava is a bit longer, about 10 inches, which transports blood to the lower body from the heart.

Both of these veins are vital for our health and well-being. Without them, our blood could not circulate properly, and we would quickly become ill. So, next time you look at your veins, remember how important they are.

The Aorta vs. Vena Cava

The aorta and the vena cava are vital to the body but they serve two different purposes. The aorta carries oxygenated blood from the heart’s left ventricle to the rest of the body and the vena cava carries deoxygenated blood from the body into the right heart atrium. Regardless of their separate functions, both are critical, and their proper function is vital for good health.

Next Up – Human Anatomy Facts

Share this post on:
About the Author

I'm a freelance writer with more than eight years of content creation experience. My content writing covers diverse genres, and I have a business degree. I am also the proud author of my memoir, My Sub-Lyme Life. This work details the effects of living with undiagnosed infections like rickettsia (like Lyme). By sharing this story, I wish to give others hope and courage in overcoming their life challenges. In my downtime, I value spending time with friends and family.

Thank you for reading! Have some feedback for us? Contact the AZ Animals editorial team.