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Types of Aneurysm
The two types of aortic aneurysm are abdominal aortic aneurysm (AAA) and thoracic aortic aneurysm (TAA).
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 located below the arteries that supply blood to the kidneys.
Abdominal Aortic Aneurysms
An aneurysm that occurs in the part of the aorta that’s located in the abdomen is called an abdominal aortic aneurysm. AAAs account for 3 in 4 aortic aneurysms. They’re found more often now than in the past because of computed tomography (to-MOG-rah-fee), or CT, scans done for other medical problems.
Small AAAs rarely rupture. However, an AAA can grow very large without causing symptoms. Thus, routine checkups and treatment for an AAA are important to prevent growth and rupture.
Thoracic Aortic Aneurysms
An aneurysm that occurs in the part of the aorta that’s located in the chest and above the diaphragm is called a thoracic aortic aneurysm. TAAs account for 1 in 4 aortic aneurysms.
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
When an aneurysm occurs in an artery in the brain, it’s called a cerebral (seh-RE-bral or SER-eh-bral) aneurysm or brain aneurysm. Brain aneurysms also are sometimes called berry aneurysms because they’re often the size of a small berry.
The illustration shows a typical location of a brain (berry) aneurysm in the arteries supplying blood to the brain. The inset image shows a closeup view of the sac-like aneurysm.
Most brain aneurysms cause no symptoms until they become large, begin to leak blood, or rupture. A ruptured brain aneurysm causes a stroke.
Aneurysms that occur in arteries other than the aorta and the brain arteries are called peripheral 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.