There are two types of aortic aneurysm: Thoracic aortic aneurysms (TAA) – these occur in the part of the aorta running through the chest; Abdominal aortic aneurysms (AAA) – these occur in the part of the aorta running through the abdomen; Most aneurysms are found during tests done for other reasons. Some people are at high risk for aneurysms.