Table 2

Modified New York Criteria for Ankylosing Spondylitis128

Note: The condition is definitely AS if the radiological criterion is associated with at least 1 clinical criterion.
Radiologic criterion
    Sacroiliitis, grade ≥II bilaterally or grade III to IV unilaterally
Clinical criteria
    Low back pain and stiffness for more than 3 months that improves with exercise but is not relieved by rest
    Limitation of motion of the lumbar spine in both the sagittal and frontal planes
    Limitation of chest expansion relative to normal values correlated for age and sex