Don't listen to those folks, I've been injecting my ribs for years and they do come out better when I do. It of course depends on what you inject them with. You do have to be careful you don't inject yourself but you also have to be careful not to cut your fingers off too so figure that one out. Go for it, it does take time to get used to doing it and toward the short bones you might have a harder time injecting but take my word for it, it is WORTH IT.
Adrian