"Obama shakes the prosthetic hand of Army Sgt. 1st Class Leroy Arthur Petry on July 12, 2011. Petry was at the White House <a href=""http://www.cnn.com/2011/POLITICS/07/12/medal.of.honor/"" target=""_blank"">to receive the Medal of Honor.</a> The Army Ranger lost his hand while tossing an enemy grenade away from fellow soldiers in Afghanistan."