Recently I have watched a variety of X-Men movies, including X-Men Origins: Wolverine and X-Men First Class. In X-Men First Class the story at the end of the movie indicates that Charles Xavier loses his ability to walk after a shot fired at Magneto hits him in his lower back.
However, at the end of X-Men Origins: Wolverine Charles Xavier is seen walking towards those who escaped.
Obviously, in both instances this is probably just artistic license changing the story. According to X-Men canon, how does Professor Xavier actually get paralysed?