The term aneurysm indicates a pocket that forms along the wall of an artery notably because of fatty deposits in the arteries or high blood pressure. It enlarges under the pressure of the blood and can sometimes reach a few centimeters, notably near the aorta. There is no clinical sign of an aneurysm as long as it does not break apart and can be present throughout the entire life of the individual without their knowledge. Aneurysms are responsible for 10% of strokes and are often fatal once they break apart, because of the associated hemorrhage. An aneurysm can be treated by surgery, by embolization, or by putting in a prosthesis when the aorta is involved.