The Black Keys Drummer -- GIANT Wave Slam Hazard ... Dislocated Shoulder

The Black Keys drummer Patrick Carney dislocated his shoulder yesterday in St. Barths ... after a humongous wave slammed him to the ocean floor.

Patrick was rushed to an ER and put under with anesthesia so doctors could reset his shoulder.

The drummer is out of the hospital and recovering ... but we're told he's still in a whole lot of pain.