Figure 1 courtesy of Intermountain Medical Imaging, Boise, Idaho. Figure 2 courtesy of Paul Traughber, M.D., Boise, Idaho.

The X-ray on the left shows a normal hand.

The X-ray on the right shows a hand with advanced rheumatoid arthritis. “Bone erosion” means cartilage and bone are worn away. “Bone displacement” means that a bone has moved out of its normal position. This X-ray shows how bone erosion and bone displacement can change the shape of the hand.