Bruce Springsteen Nails Guitar Tech in Head with Guitar During Concert

If Bruce Springsteen's guitar tech needed a refresher on who "The Boss" is, he got it ... in the form of a flying guitar that ended up striking him right in the head!!!

Now, no one's suggesting Bruce did this on purpose, but it can't make much of a difference to the stage hand's noggin after Bruce and the E. Street Band's Feb. 3 show at Atlanta's State Farm Arena.

As the band was wrapping up a tune, Bruce turned to toss his eclectic guitar to his guitar tech, Kevin Buell ... but instead of it landing in his hands -- as it has hundreds of times -- Bruce's axe hit Kevin in the head, and took him down to the ground.

Looks like Kevin just fumbled the bag this time, and Springsteen was totally surprised as he quickly went over to check on him, but he'd already exited backstage.

Bruce joked on the mic, "One man down!!!"

No word on how Kevin's doing, but we're guessing "I'm On Fire" was playing in his pounding head for a few days.