Can you get this one?

Question:

A 50-year lady from the remote village of Rajasthan presented with history of chronic back pain with spinal stiffness was referred to rheumatology clinic as a case of ankylosing spondylitis because spinal radiographs had been reported as “bamboo spine “. Previously patient had multiple spinal MRIs and x rays, orthopedic consultations, and general physician consultations without significant benefit in symptoms. In rheumatology clinic, recent investigations showed normocytic normochromic anemia, normal renal and liver function, normal ESR and CRP and negative rheumatoid factor, anti CCP antibody and ANA. Her back pain was of mechanical in nature and no history of peripheral arthritis. No other systemic issues in medical history without any history of other medical disorders. Her clinical examination showed restricted spinal movements with modified Schober’s test of 1 cm without any signs of peripheral arthritis. Further review of previous radiographs showed ossification of the attachments of tendons and ligaments and periosteal bone formations. A radiograph of forearm was requested to confirm the diagnosis.