Bechterew disease true statement?

• A. It affects women more than men.
• B. Chest expansion is reduced.
• C. HLA-B27 negative in most cases.
• D. RF positivity is typical.

Answer: (B)

Ankylosing spondylitis narrows chest expansion because inflammatory changes affect the costovertebral joints and the thoracic spine, locking the rib cage and spine together. This reduces the mobility of the chest as you inhale, so the distance between inspiration and expiration is smaller than normal.

That’s why the statement about chest expansion being reduced is true. In contrast, this disease is more common in men than women, so it does not affect women more than men. It is typically HLA-B27 positive, not negative. And rheumatoid factor is not a feature of this condition; it is usually negative, not positive.