Employee was going up the ladder to get into a L150 High Loader when he felt his thumb pop. On Monday (11/17/08) he spoke with his Supervisor who then sent him to the Clinic. He was diagnosed having a ""Mallet Thumb"", he will have a pin put in on 11/19/08 for 8 weeks. The nurse said he will have no restrictions from them, only what he feels he can and can't do.