This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Joint disorders, Subject name: Orthopaedics
Swan neck deformity is: 
Select and explain. 
A. Hyperextension at DIP, Flexion of PIP, B. Extension of DIP, Hyperflexion at PIP, C. Extension of both DIP & PIP, D. Flexion at DIP, Hyperextension at PIP
D: Flexion at DIP, Hyperextension at PIP
Answer: D: Flexion at DIP, Hyperextension at PIP 
Explanation: Deformities of RA - Swan Neck Deformity - Flexion at DIP and hypeension at PIP - Flexor insufficiency of PIP - Boutonniere deformity / Button hole deformity - Extensor deficiency at PIP joint - Hypeension of DIP & Flexion of PIP - Z deformity of thumb - Ulnar detion of fingers Z-deformity of thumb