Table 1

 New York modified criteria (1984) for ankylosing spondylitis*

(1) Low back pain with inflammatory characteristics
(2) Limitation of lumbar spine motion in sagittal and frontal planes
(3) Decreased chest expansion
(4) Bilateral sacroiliitis grade 2 or higher
(5) Unilateral sacroiliitis grade 3 or higher
*Definite AS when the fourth or fifth criterion mentioned presents with any clinical criteria