The following deformity is seen characteristically in

Deformities of Rheumatoid ahritis Swan-neck deformity: flexion posture of the DIP and hyperextension posture of the PIP joints. Buttonhole or Boutonniere Deformity: PIP in flexion, DIP in hyperextension. Wind sweep deformity: hallux valgus on one side & hallux varus on another side- produce deformity which is parallel to each other. Intrinsic plus deformity: caused by tightness and contracture of the intrinsic muscles, seen in RA, Cerebral palsy etc. Here the IP joints are in extension & MCP joints are in flexion. Z deformity: Radial detion of the wrist joint with ulnar detion of MCP joints. Pannus may form in RA, with underlying cailage destruction. With time, synol fibrosis occurs, resulting in joint stiffness Ref : Maheshwari 6e pg 282.