The two types of aortic aneurysm are abdominal aortic aneurysm and thoracic aortic aneurysm. Some people have both types.
Figure A shows a normal aorta. Figure B shows a thoracic aortic aneurysm, which is located behind the heart. Figure C shows an abdominal aortic aneurysm, which is located below the arteries that supply blood to the kidneys.
Abdominal Aortic Aneurysms
An aneurysm that occurs in the abdominal portion of the aorta is called an abdominal aortic aneurysm (AAA). Most aortic aneurysms are AAAs.
These aneurysms are found more often now than in the past because of computed tomography (to-MOG-rah-fee) scans, or CT scans, done for other medical problems.
Small AAAs rarely rupture. However, AAAs can grow very large without causing symptoms. Routine checkups and treatment for an AAA can help prevent growth and rupture.
Thoracic Aortic Aneurysms
An aneurysm that occurs in the chest portion of the aorta (above the diaphragm, a muscle that helps you breathe) is called a thoracic aortic aneurysm (TAA).
TAAs don't always cause symptoms, even when they're large. Only half of all people who have TAAs notice any symptoms. TAAs are found more often now than in the past because of chest CT scans done for other medical problems.
With a common type of TAA, the walls of the aorta weaken and a section close to the heart enlarges. As a result, the valve between the heart and the aorta can't close properly. This allows blood to leak back into the heart.
A less common type of TAA can develop in the upper back, away from the heart. A TAA in this location may result from an injury to the chest, such as from a car crash.
Other Types of Aneurysms
Aneurysms in the arteries of the brain are called cerebral (seh-RE-bral)
aneurysms or brain aneurysms. Brain aneurysms also are called berry aneurysms because they're often the size of a small berry.
Most brain aneurysms cause no symptoms until they become large, begin to leak blood, or rupture (burst). A ruptured brain aneurysm can cause a stroke.
Aneurysms that occur in arteries other than the aorta and the brain arteries are called peripheral (peh-RIF-eh-ral) aneurysms. Common locations for peripheral aneurysms include the popliteal (pop-li-TE-al), femoral (FEM-o-ral), and carotid (ka-ROT-id) arteries.
The popliteal arteries run down the back of the thighs, behind the knees. The femoral arteries are the main arteries in the groin. The carotid arteries are the two main arteries on each side of your neck.
Peripheral aneurysms aren’t as likely to rupture or dissect as aortic aneurysms. However, blood clots can form in peripheral aneurysms. If a blood clot breaks away from the aneurysm, it can block blood flow through the artery.
If a peripheral aneurysm is large, it can press on a nearby nerve or vein and cause pain, numbness, or swelling.