There are two types of aortic aneurysm: 

Thoracic aortic aneurysm: An aortic aneurysm that occurs in the part of the aorta running through the thorax (chest). One in four aortic aneurysms is a TAA. Most TAAs do not produce symptoms, even when they are large. Only half of all people with TAAs notice any symptoms. TAAs are identified more often now than in the past because of chest computed tomography (CT) scans performed for other medical problems. In a common type of TAA, the walls of the aorta become weak and a section nearest to the heart enlarges. Then the valve between the heart and the aorta cannot close properly and blood leaks backward into the heart. Less commonly, a TAA can develop in the upper back away from the heart. A TAA in this location can result from and injury to the chest such as from an auto crash.

Abdominal aortic aneurysm:  An aortic aneurysm that occurs in the part of the aorta running through the abdomen. Three in four aortic aneurysms are AAAs. An AAA can grow very large without producing symptoms. About 1 in 5 AAAs rupture. 

It is often not until an aneurysm ruptures or grows large enough to press on nearby parts of the body or block blood flow that it produces any signs or symptoms. Most abdominal aortic aneurysms (AAAs) develop slowly over years and have no signs or symptoms until (or if) they rupture. Sometimes, a doctor can feel a pulsating mass while examining a patient's abdomen. 

When symptoms are present, they can include: 

Deep penetrating pain in your back or the side of your abdomen

Steady gnawing pain in your abdomen that lasts for hours or days at a time

Coldness, numbness, or tingling in your feet due to blocked blood flow in your legs 

If an AAA ruptures, symptoms can include: 

Sudden, severe pain in your lower abdomen and back

Nausea and vomiting

Clammy, sweaty skin

Lightheadedness

Rapid heart rate when standing up. 

Internal bleeding from a ruptured AAA can send you into shock. Shock is a life-threatening condition in which the organs of the body do not get enough blood flow. 

A thoracic (chest) aortic aneurysm may have no symptoms until the aneurysm begins to leak or grow. Signs or symptoms may include: 

Pain in your jaw, neck, upper back (or other part of your back), or chest

Coughing, hoarseness, or trouble breathing 

Most aneurysms (3 out of 4) are found by chance when a diagnostic test, such as x ray or ultrasound, is performed for a different reason. Many cases of ruptured aneurysm can be prevented with early diagnosis and medical treatment. Medicines and surgery are the two main treatments for aneurysms. Medicines may be prescribed before surgery or instead of surgery. To prevent an aneurysm and keep blood vessels healthy, quit smoking, eat a low-fat, low-cholesterol diet, get regular physical activity, and control high blood pressure and high cholesterol.