An aortic aneurysm is a weak, bulging area in the wall of the aorta. The bulging develops from a weakness or defect in the aortic wall and tends to get bigger with time. The aorta is the body's largest artery. It carries blood from the heart for delivery to the rest of the body. The aorta travels through the chest (thoracic aorta) and the abdomen (abdominal aorta). Abdominal aortic aneurysms are more common than thoracic aortic aneurysms.
The greatest danger is that an aneurysm will rupture. This will cause heavy, uncontrollable bleeding (hemorrhage). Aortic aneurysms can also occur with aortic dissection. Dissection is defined as a small tear in the aortic wall. Blood from the aneurysm can leak through this tear and spread between the layers of the aortic wall, eventually leading to rupture of the vessel.
Aneurysms can develop anywhere, but are most common in the aorta, iliac artery, and femoral artery.