The arm is gone from disc degeneration, the nerves that control the muscles are compressed by his vertebrae, lot of guys who went hard and heavy in the gym back in the day end up with spinal issues and muscular atrophy at the effected muscle related spinal level. Priest Coleman Cutler etc, I have three replaced discs in my spine from similar, on saying that Flex looks like he's let his go a long time, most people, jump on it at the pain stage or certainly the first sign of atrophy. I lost my right side, 12 year post op it improves but you will never be symmetrical again, its the big equaliser as far as bodybuilding and life goes, you can no longer get bigger as the nerve effected side won't grow and the other side will. Basically if you weren't retired you are.
