This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Orthopaedics
Which joint is spared in Rheumatoid arthritis - 
Select and explain. 
A. MP joints of hand, B. DIP joints of finger, C. PIP joints of finger, D. Atlanto-axial joint
B: DIP joints of finger
Answer: B: DIP joints of finger 
Explanation: Of particular importance is the sparing of distal interphalangeal joint.