Sorry I keep airing out here but this just keeps getting better and better! (sarcasm) I was scratching my right bicep the opther day and noticed a trence down the center of it from almost my shoulder to my elbow on top of my arm where you flex your muscle. The other arm does not have this and I have never noticed this before. I know I would have. I had a doc at the hospital where IO work look at it and he said it was a vein track but why is there none on the other side? You can't see the trench probably because I am too fat and as far as I know I don't have any weakness in this arm. My question is this: Could this be atrophy? Can you have atrophy without weakness? I always thought that weakness would come first then atrophy. Any thoughts?