Which physical examination finding indicates restricted chest movement in Ankylosing Spondylitis?

• A. Normal chest expansion
• B. Decreased chest expansion
• C. Increased chest expansion
• D. Pain-free expansion

Answer: (B)

In Ankylosing Spondylitis, inflammation and eventual fusion of the spine and costovertebral joints limit how the rib cage can move during breathing, producing a restrictive chest-wall movement. On exam, you test chest expansion by placing your hands on the posterior lower rib cage and asking the patient to take a deep breath; the distance between your hands should increase with inspiration. In AS, this expansion is reduced, so decreased chest expansion is the best indicator of restricted chest movement. Normal expansion would indicate no thoracic involvement, increased expansion is not typical, and pain-free expansion doesn’t specifically reflect the degree of movement.