Hemorrhagic infarction may be seen in places where some collateral flow can occur, as in the bowel, shown here at autopsy with marked dark red ischemic small bowel. Ordinarily, it is difficult to infarct the small or large bowel, because of an extensive anastomosing blood supply. Typically, severe compromise of at least 2 of the 3 major arterial supplies (celiac trunk, superior mesenteric, inferior mesenteric) is required for infarction to occur. Such arterial compromise is most likely to occur with severe atherosclerosis (often with diabetes mellitus) and with vasculitis (as with classic polyarteritis nodosa). Of course, cardiac failure with severe hypotension can produce a similar result.