EE WAS PERFORMING MAINTENANCE CHECK. AFTER DETERMINING, HE NEEDED ADDITIONAL TRANSMISSION FLUID, HE LAID DIPSTICK ON CATWALK AND BEGAN BACK AND DOWN STEPS OF LOADER IN FLUID WHEN HE MISSED A F STEP, FELL BACKWARDS STUMBLED AND HEAD WHIPPED BACKWARDS HITTING TIRE OF LOADER PARKED BRUIDE THE ONE LACERATION TO BACK OF HEAD REQUIRING STITURES.