What is aorta?

The aorta is the main artery in the human body, originating from the left ventricle of the heart and extending down to the abdomen, where it splits into two smaller arteries (left and right common iliac arteries). The aorta distributes oxygenated blood to all parts of the body through the systemic circulation. In anatomical sources, the aorta is usually divided into two sections by diaphragm, where the thoracic aorta runs from the heart to the diaphragm, and the abdominal aorta runs from the diaphragm to the aortic bifurcation.

What is aortic aneurysm?

An aortic aneurysm is enlargement of part of the aorta to greater than 1.5 times normal size (usually happened at the weakness part of the aorta wall). It is like a bulge when you over inflated the bike tire, with the accumulation of the pressure, the bulge will get bigger. They usually cause no symptoms except when ruptured. When rupture occurs, massive internal bleeding results and, unless treated immediately, shock and death can occur. They are most commonly located in the abdominal aorta (Abdominal aortic aneurysms), but can also be located in the thoracic aorta (Thoracic aortic aneurysms).

Classification:

Aortic aneurysms are classified by their shape to true aneurysms, false aneurysms (pseudoaneurysm), and arterial dissection.

True aneurysm

It is the partial and terminal enlargement of the aorta to greater than 1.5 times normal size. Common aortic aneurysms are thoracic aortic aneurysms and abdominal aortic aneurysms.

Pseudoaneurysm

A pseudoaneurysm, also known as a false aneurysm, is a hematoma that forms as the result of a leaking hole in an artery; mostly caused by trauma.

Arterial dissection

Tear within the wall of a blood vessel, which allows blood to separate the wall layers. By separating a portion of the wall of the artery, a dissection creates two lumens within the vessel, the true lumen, and the "false lumen". The false lumen will keep extend to affect blood supply of thoracic and abdominal organs. Most common and dangerous are thoracic aortic dissection, it can extend to abdominal aorta even iliac artery.

Difference between aortic aneurysm and tumor; is it malignant?

Aortic aneurysm is not malignant tumor. Tumor is an abnormal growth of tissue; an aneurysm is a localized, blood-filled balloon-like bulge in the wall of a blood vessel. It is benign but can be very dangerous. If the bulge keeps increase in size, the risk of rupture increase, rupture could lead to bleeding and subsequent hypovolemic shock, leading to death.