Aortic aneurysm:An outpouching (a local widening) of the largestarteryin身体,aorta, involving thatvesselin its course above the diaphragm (thoracicaorticaneurysm) or, more commonly, below the diaphragm (abdominal aortic aneurysm). Thediagnosisof an aortic aneurysm can be straight forward or difficult. Around 1900 the eminentphysicianWilliam Osler said: "There is nodiseasemore conducive toclinicalhumility than aneurysm of the aorta." At the area of the aneurysm, there is typically a bulge and the wall is weakened and mayrupture. Because of the volume ofbloodflowing under relatively high pressure through the aorta, a ruptured aneurysm of the aorta is a catastrophe.
The word "aneurysm" comes from the Greek "aneurysma" meaning "a widening."
