A driver was pulling a pallet of dry product onto the liftgate of a delivery truck using a manual pallet jack. The weight of the pallet pushed him back against the chain on the liftgate causing him to lose balance and fall backward. His right leg was pinned between the pallet, the manual jack, and the chain. The driver was holding onto the chain while hanging from the gate and was able to pull his leg free. The driver was hospitalized with a broken right lower leg.