Look bella, if you have a dent right now without weakness, it is not atrophy.
If you have TWO SYMMETRICAL DENTS, I don't care even if you have weakness, it IS NOT ATROPHY. Quoting from the BFS forum, God decided to make these dents in your body so that the muscles and tendons would fit and operate better, it's as simple as that.
EMGs will detect problems before you are symptomatic if there is a problem: end of story. If the EMG is done when you actually have atrophy, the EMG will DEFINITELY detect a problem. The only way it wouldn't detect it would be if the person administering the EMG was in fact, a lab monkey. It doesn't matter whether the EMG was surface or needle.