This document discusses ankylosing spondylitis (AS), a type of spinal arthritis. It begins by listing various synonyms for AS. The document then covers the definition, symptoms, causes, pathology, clinical features, radiological features, diagnosis, and management of AS. Key points include that AS is a seronegative inflammatory arthritis affecting the spine, it commonly improves with exercise and worsens with rest, and causes pain, stiffness, and fusion of the spinal joints over time if left untreated. Diagnosis involves meeting criteria related to symptoms and imaging findings. Treatment involves medications and physical therapy.