EE WAS USING A HAMMER TO DRIVE A BUSHING INTO PLACE. MISSED TOOL THAT WAS BEING USED TO DRIVE BUSHING INTO PLACE CAUSING HAMMER TO STRIKE THUMB. FINISHED SHIFT, TWO DAYS LATER THUMB WAS STILL SORE/SWOLLEN. EXAMINED BY PHYSICIAN. ON 8/26/05 HE WAS INFORMED BY PHYSICIAN THAT THUMB HAD A FRACTURE