EE WAS HELPING MECHANIC, MAN UNPIN THE HORSE BACKHOE ATTACHMENT AT THE JAWS INORDER TO REMOVE IT. HE GRABBED A BRACE TO ADJUST HIS FOOTING AT THE SAME TIME OTHER HIT THE BRACE WITH A 3 LBS. SH OP HAMMER, SMASHING HIS THUMB LACERATION IT. HE WAS THEN ADMINISTERED FIRST AID BY HIS SUPERVISOR OTHER BY WRAPPING THE HAND AND THUMB AND APPLYING ICE. THEN TRANSPORTED TO CLINIC.