lovenox injections: SC, but where?

I was told by a seasoned nurse that lovenox (enoxaparin) is never given anywhere but in the abdomen, especially not in the arm. My drug book simply says give only in abdomen (but doesn't say why not elsewhere), but my pharmacology text does not specify location, just that it is given SC. I have done a search on the web and find reputable journal articles showing that it is given SC in abdomen and arms. I am trying to determine the pathophysiology against using the fatty tissue over the triceps. I need to understand why the arm is no good for lovenox. I saw a patient with extensive bleeding in the arm from a lovenox injection, but by his description of how much the injection hurt, I would guess it was not a SC but an IM injection. I would appreciate being pointed in the direction of a source with the answer to this question. I'm trying to develop my practice based on evidence. Thanks!