Which of the following region of spine is most commonly affected in rheumatoid ahritis?: (A) Cervical spine, (B) Thoracic spine, (C) Lumbar spine, (D) Sacral spine
Answer is A. Rheumatoid ahritis principally involves atlantoaxial joint of cervical spine. Atlantoaxial involvement of the cervical spine result in compressive myelopathy and neurologic dysfunction. Rheumatoid ahritis does not affect thoracic and lumbar spine except in unusual circumstances. Reference: Harrison's Principles of Internal Medicine 18e chapter 321.