<prompt> Earliest sign indicative of sacroilitis on X ray is?OsteophytesErosionBlurring of SI jointSclerosis  <response>: Ans. is c i.e., Blurring of SI joint Radiographically, the earliest sign of sacroiliitis is indistinctness of the joint The joints initially widen before they narrow.Radiographic Sacroiliitis grading New York criteriai Grade 0: normalii Grade 1: some blurring of the joint margins - suspiciousiii Grade 2: minimal sclerosis with some erosioniv Grade 3a Definite sclerosis on both sides of jointb Severe erosions with widening of joint space with or without ankylosisv Grade 4: complete ankylosis 