TWO PEOPLE HAD UNLOADED CORE BOX'S FROM BACK OF PICK-UP. INJURED PERSON WAS GOING AROUND BACK OF TRUCK AND LOST BALANCE. HIS LEFT HAND REACHED OUT TO TRUCK BED AS OTHER PERSON WAS CLOSING THE TAILGATE. INJURED PERSONS HAND WAS CAUGHT BETWEEN TAILGATE AND BED OF TRUCK CAUSING INJURY TO LEFT HAND. REQUIRED 2 SUTURES.