1984 Modified New York Criteria for AS

Clinical Criteria

  • Low back pain ≥ 3 months, improved by exercise and not relieved by rest
  • Limitation of lumbar spine in sagittal and frontal planes
  • Limitation of chest expansion (relative to normal values corrected for age and sex)

Radiological criteria

  • Bilateral grade 2-4 sacroiliitis OR
  • Unilateral 3-4 sacroiliitis

Requirements: bilateral grade 2-4 or unilateral grade 3-4 sacroiliitis AND any clinical criteria (see XRay Grading of SI joints).

Reference: Van der Linden et al.  Arthritis Rheum 1984;27:361.