Thoracic aneurysm

A local
widening and bulging of a vessel ( an aneurysm ) within the
thorax ( chest ) . See: Aortic aneurysm. An aneurysm is a
localized widening ( dilatation ) of an artery, vein, or the
heart. At the area of an aneurysm, there is typically a
bulge and the wall is weakened and may rupture. The word
"aneurysm" comes from the Greek "aneurysma" meaning "a
widening."