How can I point a player's arm to where the camera is looking?

I am trying to make an FPS type of game. Right now if I look too far up or down the weapon in my hand goes out of the frame. The gun is still there and functions fine, but it bothers me that if I were to look up or down to shoot I may not be able to even see the gun depending on how far up or down I'm looking. Is there a way to sort of "bind" the right arm and the camera direction so that no matter how far up or down I look the gun will always be in the frame?