You'd have to be an idiot to go through with spot injecting any muscle that's in such close proximity to the spinal chord. The nerve density is so high that only a doctor with specialized training can do it safely. I know this because two years ago I was having bad back problems. A doc in my hometown who is an anesthesiologist and pain specialist injected the spasming spinal erectors to give me relief. Well, the next day when I was back at school (different city), the freezing came out. I went to a walk-in clinic and asked the general practitioner there to repeat the procedure. He refused immediately, citing the risks. I was mad, and told him that there was already a needle mark there to guide him....but there was no way he'd risk it. If a medical doctor is wary of injecting the spinal erector, why in blue blazes would you even consider risking it??? (BTW, this applies to the traps to, for those of you considering spot injecting there.)