1998 FORD RANGER FIVE SPEED FOUR SHE'LL DRIVE, WAS PARKED ON LEVEL SURFACE PARKING BREAK ENGAGED TRANSITION IN GEAR IGNITION OFF AND LOCKED KEY REMOVED, VEHICLE BEGAN GAINING SPEED ROLLING AWAY BACKWARD IN FIRST GEAR I TRIED TO JUMP IN TO STOP VEHICLE USING BREAKS, AT WHICH TIME VEHICLE GAINED SPEED AND FLUNG ME UNDER TIRE. I RECEIVED FIVE STITCHES ROAD BURN AS WELL AS A SOFT CAST AND SPLINT.