Thoracic aneurysms are a bulging of the largest artery in the body, the aorta, and occur specifically in the chest area. Aneurysms affecting other parts of the aorta are diagnosed as abdominal aneurysms. Aneurysms occur when the wall of a blood vessel weakens over time and begins to expand or leak. Thoracic aneurysms are rare, but do not always exhibit symptoms in early and more treatable stages. Once an aneurysm tears or ruptures, symptoms may include clammy skin, rapid heart rate, chest pain, nausea and vomiting. A ruptured thoracic aneurysm is an emergency and should be treated immediately. Healthy lifestyle choices that prevent chronic conditions which may lead to a thoracic aneurysm are the best way to avoid this condition.