Dear consuelo: If you mean you have only two bones in your thumb, that is something I have never seen. I have see babies with a tiny second thumb attached to base of thumb, but not capable of motion. Up in Maine I saw a guy with two index fingers on each hand but no thumb. His neighbors called him "Five finger Joe." Imagine him playing a piano. Didn't seem to bother him, although he could not touch tip of little finger with the extra index finger. I didn't ask him if he had trouble thumbing rides.