Figure 10.

(A) Frontal radiographs of the pelvis show a large para-acetabular osteophyte (open arrows), irregular projections of bone or whiskering at the sites of tendinous insertion at the iliac crests, ischial tuberosities, anterior superior iliac spines and lesser trochanters, ossification along the iliolumbar and sacrotuberous ligaments (solid arrows), para-articular osteophyte along the inferior and superior margin of the sacroiliac joint; (B, C) Lateral radiographs of the cervical and lumbar spine demonstrate flowing ossification along the anterior aspect of vertebral bodies (open arrows) separated from the body and thicker than syndesmophytes of ankylosing spondylitis; thickening and ossification of the posterior longitudinal ligament (black arrows) and preserved disc spaces, post-operative laminectomy defect in the cervical spine was also noted; (D) Axial CT image of the sacroiliac joints shows juxta- and intra-articular bridging ossification with absence of articular surface erosion. The absence of erosions and joint space narrowing of the sacroiliac joint as well as facet joint ankylosis differentiate this disease from ankylosing spondylitis, and normal bone density differentiates it from fluorosis.