This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Orthopaedics
Swan neck deformity is seen in 
Select and explain. 
A. Osteoahritis, B. Rheumatoid ahritis, C. Psoriatic ahritis, D. Gout
B: Rheumatoid ahritis
Answer: B: Rheumatoid ahritis 
Explanation: Impoant deformities of hand in RABoutonniere deformity: flexion contracture of PIP joint and extension of DIP jointSwan neck deformity: Hyperextension of PIP joint and flexion at DIP jointZ-deformity: radial detion of the wrist with ulnar detion of fingersHyperextension of 1st interphalangeal joint and flexion on MP joint(Refer: Mohindra's Fundamentals of Ohopedics, 2nd edition, pg no. 420)