The affect of rheumatoid arthritis can progress to the degree that it is crippling. Deformities distinctive to late-stage rheumatoid arthritis such as ulnar deviation of the bones of the hands, or swan-neck deviation of the fingers occur because muscles and tendons on one side of the joint may overpower those on the other side, pulling the bones out of alignment.
Review Date: 3/22/2013 Reviewed By: Ariel D. Teitel, MD, MBA, Clinical Associate Professor of Medicine, NYU Langone Medical Center. Review provided by VeriMed Healthcare Network. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, Bethanne Black, Stephanie Slon, and Nissi Wang.