What is the difference between aortic aneurysm and a regular aorta?

Ballooning: In an aneurysm, a segment of the aorta dilates or balloons out. We measure the diameter of the blood vessel to see how severe that ballooning is. There is a weak area in the artery and as the artery expands, the risk that it could rupture increases.

Cystic medial necros: Cystic medial necrosis weakens the arterial wall and the blood pressure inside the aorta dilates the aorta. Aneurysmal dilatation of the aorta occurs until eventual rupture may occur.

Size: A true aneurysm is dilatation of a blood vessel one and half times normal size. For the aorta the normal size varies between different segments, age and gender. For example abdominal aorta below the kidney arteries measures around 1.8-2 cm in diameter in young males .. So it will become an aneurysm at 3 cm size.

A buldge: When a weak area of the abdominal aorta expands or bulges, it is called an abdominal aortic aneurysm (aaa). The pressure from blood flowing through your abdominal aorta can cause a weakened part to bulge, much like a balloon. A normal aorta is about 1 inch in diameter. However, an AAA can stretch the aorta beyond its safety margin as it expands. AAA are a risk because of rupture (usually 5-5.5 cm).