WHILE OPERATING A SCRAPER, THE RIGHT REAR BOUNCED OVER A CHUNK OF MATERIAL WHICH CAUSED A MUSCLE SPASM IN EE'S LOWER BACK. HE WAS SEEN AT THE ER & DIAGNOSED WITH A LOWER BACK STRAIN. HIS CONDITION DID NOT IMPROVE SO HE VISITED A SPECIALIST 7/19/04. THE SPECIALIST DIAGNOSED HIM WITH A L4 HNP (HERNIATED NUCLEUS PULPOSUS) & PRESCRIBED THERAPY, ANTI-INFLAMATORY & MUSCLE RELAXERS.