While running 13 3/8” casing, the company man requested the fill line length to be extended. The casing company did not have the proper joints available, so it was decided to add a Kelly valve to the Kelly. The top drive was put in the extended position to clear the well hole, which contained the casing. Spider elevator was placed beside the well hole. The extension was placed on the rig floor and not in the mouse hole due to it being covered and not available. The crew was attempting to hold onto the fill line arrangement with the air hoist line and chain sling on one side and supported on the other side by the left side (back up tong)rig tong. The IP was placed in between the left rig tong and the spider elevator to support the tong while make up torque was applied. Due to make up torque from the top drive, the fill line arrangement and the left rig tong moved toward IP who was trapped by the spider elevator and struck him in his right arm causing a fracture.