1.   Aneurysms most often occur in the chest, abdomen and brain.

2.   Aneurysms typically occur when an artery wall wears out.

3.   Giangola said that no one knew how often such aneurysms occurred.

4.   In the chest, aortic aneurysms occur most commonly in the descending portion as the artery curves downward after its branches supply blood to the neck and head.