THESE cases are reported to call attention to the association of severe sciatica with nerve compression from a pelvic aneurysm. Surprisingly this relation could be found only once described in the older literature.§ Its recognition is important since progress in reconstructive vascular surgery has made it possible to treat such aneurysms successfully, with prolongation of a comfortable life.Case ReportsCase 1. H.P.K. (M.G.H. 77–34–43), an 80-year-old man, entered the hospital on December 11, 1958, because of acute fever, vomiting and diarrhea. He had been under treatment during the previous 6 years for hypertensive arteriosclerotic heart disease, angina pectoris and . . .