<prompt> 40 years patient having arthritis of PIP and DIP along with carpometacarpal joint of thumb and sparing of wrist and metacarpophalangeal joint, most likely diagnosis isrheumatoid arthritisosteo arthritispsoriatic arthritispseudo gout  <response>: Ans. is b i.e.osteoarthritis Now, this form of question where arthritic involvement of a group of joints are given is very frequently asked:Osteoarthritis- Joints involved :PIP, DIP, Base of thumbSparing of wrist metacarpophalangeal junction.Psoriasis: - Joints involved :PIP, DIP, Wrist, metacarpophalangeal joint.Rheumatoid arthritis - DIP is not involved characteristically.Joints involvedMetacarpophalangeal joints MC esp of index finger PIP, wrist, elbow, knee, ankle. 