Overview. The aorta is the main artery that carries blood from the heart to the rest of the body. The aorta comes out from the left ventricle of the heart and travels through the chest and abdomen.A thoracic aortic aneurysm (TAA) is an abnormal bulge or ballooning in the wall of the aortic artery running through the thorax (chest).One in four aortic aneurysms are TAAs.An aneurysm that occurs in the part of the aorta running through the abdomen is an abdominal aortic aneurysm (AAA) . Three in four aortic aneurysms are AAAs. An aneurysm that grows and becomes large enough can burst, causing dangerous, often fatal, bleeding inside the body.ne in four aortic aneurysms are TAAs. An aneurysm that occurs in the part of the aorta running through the abdomen is an abdominal aortic aneurysm (AAA) . Three in four aortic aneurysms are AAAs. An aneurysm that grows and becomes large enough can burst, causing dangerous, often fatal, bleeding inside the body.