My injections were in the bis, tris and outer delts. The WHOLE ARM was bruised, from forearm to shoulder. Don't know which parts of the arms have more fat, but it didn't appear to make any difference.
Gotta say, my current AA mix is working fine, but the pain in my elbows and shoulders from the IFG is a real drag. I added a couple of pounds and kept my waist the same. But I think I would be better off just doing a bulker and then a quick cutter to knock off a few pounds. But I got the same pains taking HGH, so I am probably prone to this. Hell, I even get it when I am on nothing. Right now I am also taking 500 mg of deca a week.