Difference Between Ascending and Descending Aorta

The key difference between ascending and descending aorta is that ascending aorta is the upward part of the arch and the aortic section closest to the heart while descending aorta is the downward portion of the arch that is connected to a network of arteries and supplies most of the body with oxygen-rich blood.

Aorta is the largest artery in the human body. It carries oxygenated blood from the heart to all other parts of the body except the lungs. It is situated at the top of the heart. It originates from the left ventricle of the heart and is a part of the systemic circulation. There are several sections of the aorta. They are the ascending aorta, aortic arch, descending thoracic aorta and the abdominal aorta. Ascending aorta is the section which is closest to the heart. Therefore, it is the upward portion of the arch while descending aorta is the downward portion of the arch.

CONTENTS

1. Overview and Key Difference
2. What is Ascending Aorta
3. What is Descending Aorta
4. Similarities Between Ascending and Descending Aorta
5. Side by Side Comparison – Ascending vs Descending Aorta in Tabular Form
6. Summary

What is Ascending Aorta?

Ascending aorta is the first part of the aorta, and it arises from the aortic orifice from the left ventricle and extends up to the aortic arch. Therefore, ascending aorta is the closest section of the aorta to the heart. It is the upward part of the arch. It is 2 inches long and travels with the pulmonary trunk. Two coronary arteries (the right coronary artery and the left coronary artery) are the only branches of the ascending aorta. These two arteries supply blood to heart muscles.

What is Descending Aorta?

Descending aorta or thoracic aorta is the third section of the aorta. It spans from the level of T4 (fourth thoracic vertebra) to T12 (twelfth thoracic vertebra). The descending aorta runs inferiorly. It continues from the aortic arch and descends in the thoracic cavity and then becomes the abdominal aorta.

The vertebral column is located behind the descending thoracic aorta. Bronchial arteries, mediastinal arteries, oesophagal arteries, pericardial arteries, superior phrenic arteries, intercostal and subcostal arteries are the branches arising from descending aorta.

What are the Similarities Between Ascending and Descending Aorta?

• Ascending and descending aorta are two of the four sections of aorta.
• Both carry oxygenated blood.
• Ascending aorta becomes the aortic arch while descending aorta continues from the aortic arch.
• Both have branches arising from them.

What is the Difference Between Ascending and Descending Aorta?

Ascending aorta is the first part of the aorta which begins at the aortic valve, extends 2 inches and becomes the aortic arch while descending aorta is the third portion of the aorta which spans from the level of T4 to T12 and becomes the abdominal aorta. So, this is the key difference between ascending and descending aorta.

Moreover, ascending aorta branches off to two coronary arteries while descending aorta branches off to bronchial arteries, mediastinal arteries, oesophageal arteries, pericardial arteries, superior phrenic arteries, intercostal and subcostal arteries.

Below infographic shows the differences between ascending and descending aorta in tabular form.

Summary – Ascending vs Descending Aorta

Ascending and descending aorta are the first and third sections of the aorta, respectively. Ascending aorta rises up from the heart and is about 2 inches long. The coronary arteries branch off the ascending aorta to supply the heart with blood. The descending aorta runs inferiorly and it continues from the aortic arch and descends in the thoracic cavity and then becomes the abdominal aorta. It branches off to several arteries that supply blood to ribs and some chest structures. Thus, this is the summary of the difference between ascending and descending aorta.

Reference:

1. Hoffman, Matthew. “The Aorta (Human Anatomy): Picture, Function, Location, and Conditions.” WebMD, WebMD, 28 June 2020, Available here.
2. “The Heart.” Boundless Anatomy and Physiology. Lumen, Available here.

Image Courtesy:

1. “Aorta segments” By User:Mikael Häggström, by Edoarado – Source image: en:File:Aorta scheme noTags.svg by Edoarado (CC-BY-SA 3.0) DOI:10.1016/j.crvasa.2015.05.001. ISSN 00108650. Available here.
2. “Gray530” By Henry Vandyke Carter – Henry Gray (1918) Anatomy of the Human Body. Bartleby.com: Gray's Anatomy, Plate 530 (Public Domain) via Commons Wikimedia