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: Surgery
Heberden node denotes involvement of ? 
Select and explain. 
A. Distal inetrphalangeal joint, B. Proximal interphalangel joint, C. Metacarpophalangeal joint, D. Metatarsophalangeal joint
A: Distal inetrphalangeal joint
Answer: A: Distal inetrphalangeal joint 
Explanation: Ans. is 'a' i.e., Distal inetrphalangeal joint In osteoahritis of hand : i) Distal interphalangeal joint :- Heberden's node ii) Proximal interphalangeal joint :- Bouchard's node