import fbx skeleton animtion problem

Hi there, I am just a new to Unity and got a problem while I was trying to import a FBX file into it. It's a 3d model with skeleton animation and I made it in maya. It looks fine while I put it back to maya and 3d max, but while it imported it into Unity, the skeleton animation part didn't work well. The shape of the poly which got rigs has changed like it shows in the images,but other polys are looks great. Can you plz help me solve this problem? I tested a lot but it still does not work...help!THANKS A LOT!