The Human Aorta

All illustrations are used with permission from Baylor College of Medicine.

The Human aorta is the largest artery in the human body, it’s shaped like a candy cane with the heart attached to the short end and about the size of a garden hose. It slowly decreases in size as it descends and passes through the abdominal area where it splits into two about at the level of the belly button.

This magnificent highway is made of smooth muscle cells and elastic tissue. It consists of three layers: the tunica adventitia (the outer layer), the tu – nica media (middle layer), and the tunica intima (the inner layer).

Whether you like lima beans or not here’s a way to remember it from the inside out L.I.M.A., Layers equals intima, media adventia.

The aorta is the highway the carries oxygenated blood from the heart to the rest of the body. There are 19 major exits (arteries) along this highway from exit one the coronary arteries that feed the heart to exit 19 the iliac arteries that split and descend into the legs.

Here are the five sections of the aorta:

1. The Root – Where it originates from the heart.

2. The Ascending Aorta – The northbound section from the heart to the arch.

3. The Aortic Arch – Where it looks like an upside down letter U and the arteries for the arms, head, and neck arise.

4. The Descending Thoracic Aorta – Starting at the arch southbound (descending aorta) passing through the chest area.

5. The Abdominal Aorta – Where the southbound descending aorta emerges from the diaphragm into the abdominal cavity (the stomach area); then bifurcates (splits in two) around the belly button and heads down each leg as the iliac arteries.


What are often called “Smooth Criminals” because they go undetected and sometimes mimic other abnormalities Thoracic aortic aneurysms and dissection in the chest can go undetected for long periods
of time.

Thoracic aortic dissection (TAD) is the most common rapid or abrupt onset, generally with a short, severe course and requiring prompt treatment of all the acute aortic syndromes.

TAD and thoracic aortic aneurysms (TAA) are very closely related. In fact, TAA is a well-known risk factor for TAD. Likewise, on the flipside, TAD is a common cause of TAA, due to the progressive growth of the torn aortic wall.

Although the two go hand in hand, many times a person with a TAA will not experience TAD.

Types of Aortic Dissections The DeBakey System , named after surgeon and aortic dissection sufferer Dr. Michael E. DeBakey, is an anatomical description of the aortic dissection. It categorizes the dissection based on where the original intimal tear is located and the extent of the dissection (localized to either the ascending aorta or descending aorta, or involves both the ascending and descending aorta).

Type I – Originates in ascending aorta, covers at least to the aortic arch and often beyond it distally (downward).

Type II – Originates in and is confined to the as – cending aorta. Type III – Originates in descending aorta, rarely extends proximally (the point of attachment).

Aortic Dissection

Stanford Classification System Divided into two groups, A and B, depending on whether the ascending aorta is involved. A = Type I and II DeBakey B = Type III DeBakey

Thoracic Aortic Aneurysms

An aneurysm is a localized or diffused (spread out over an area) dilation of an artery with a diameter at
least 50 percent greater than the normal size of the artery. The human aorta in the chest area is approximately 2.54 cm wide (about an inch across).

Aneurysms that occur in the thoracic aorta are identified as thoracic aneurysm (TA). Aneurysms that coexist in both seg – ments of the aorta (thoracic and abdom – inal) are identified as thoracoabdominal an- eurysms.

Abdominal Aortic Aneurysms (AAA)

Aneurysms are much more common in this area than in the chest. AAA are often discovered during routine check ups when a pulsating mass is felt in the stomach. The aorta in the stomach region is only about
2 cm, aneurysms larger than this are monitored for potential growth.

Each year, physicians diagnose hundreds of thousands of people in the United States with AAA. Fortunately, especially when diagnosed early before it causes problems it can be medically managed and treated in needed.

Several hundred thousand gallons of  blood will pass through your aorta every year, it’s imperative for you to maintain this highway through diet and exercise.

As this site and our organization grows, we’ll provide more information and tools for you to stay informed about the highway within you.

Please note: The material on this site should not take the place of the care you receive from a personal physician. It is written to give you a basic understanding of the purpose and function of the aorta, aortic dissection, and thoracic and abdominal aneurysms. This information is not intended as diagnostic or therapeutic aid. You should seek prompt medical care for any specific health issues. Please consult your physician!

Sources Society of Thoracic Surgery, Society of Vascular Surgery



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