Orthopaedics Differentiating point between psoriatic and rheumatoid arthritis and ankylosing spondylitis? A Pencil-in-cup deformity B Telescoping of phalanges C Marginal erosions D All of the above 💡 Explanation Differentiating point between psoriatic and rheumatoid arthritis and ankylosing spondylitis? ✓ Correct Answer: D. All of the above