A 53-year-old man with a 5-year history of type 2 diabetes and hypertension presents to the outpatient department complaining of progressively worsening backache and stiffness for the past 6 months. He describes initial mild back discomfort that progressed to continuous pain accompanied by limitation of forward and side-to-side bending. He now has difficulty with sitting cross-legged, stooping, and rising from bed without support. His degree of stiffness does not vary over the course of the day, but it is slightly relieved with movement. He also reports 3 months of similar pain and stiffness involving his neck. There is no history of a fall, significant trauma, unusual weight lifting, bone pain, or symptoms of extra-axial joint involvement. He also denies a history of fever, rash, oral ulcerations, ocular symptoms, or urinary symptoms.