ON A SNOWY MORNING, EE WAS ASSISTING A CO-WORKER WITH THE UNLOADING OF A FLATBED TRAILER. HE STEPPED ON A BOARD WHILE ON THE TRAILER AND IT MOVED ALLOWING HIS LEFT LEG TO FALL THROUGH AND HE L ANDED ON A BEAM AS A RESULT. THE FOREMAN ASKED HIM IF HE WAS OK AND HE SAID HE WAS. HOWEVER HE CAME TO OFFICE ON 2/7/00 & REPORTED LOW BACK PAIN. WHEN SEEN BY DR ON 2/10 DIAGNOSIS-SACROILIITI