The essential feature of a traumatic aneurysm is that it is produced by some form of injury which divides all the coats of the artery.
The risk of gangrene is diminished by a course of digital compression of the femoral artery, before operating on the aneurysm.
The rupture of a popliteal aneurysm, however, by compressing the vein and the articular branches, usually determines gangrene.
They usually heal rapidly, but, like punctured wounds, are liable to be followed by the formation of an aneurysm.
When the bleeding is profuse, however, the parts beyond the aneurysm become greatly swollen, livid, and cold, and the pulse beyond is completely lost.
Histological examination showed a normal atrioventricular node and bundle, adjacent to the aneurysm.
The aneurysms ruptured into the right ventricle in 73%, into the right atrium in 27% and into the left ventricle in less than 1%.
Besides these, aneurysms are seen in the transition from muscular to elastic segments in such arteries as the celiac and mesenteric.
