A Contract employee had just slid a hog panel on the ATRS. EE pulled the roof bolter up to the next row and set the ATRS. EE started swinging the boom out and had EE's left hand resting on the handle under the canopy. As EE swung the boom out, EE's elbow hit the rib which caused EE's wrist to fold striking it under the canopy, causing a fracture to EE's wrist.