Ankylosing Spondylitis

A 66-year-old man had progressive reduction of global spine movement for more than two decades that eventually resulted in complete spinal immobility. Extensive calcification of the intervertebral ligaments, bilateral ossification of the outer layer of the annulus fibrosis (forming bony bridges called marginal syndesmophytes), and apophyseal joint ankyloses all gave the appearance of a bamboo spine, as shown in Panel A. Bilateral symmetric sacroiliitis, caused initially by erosive disease and subsequently by bony ankylosis, can be seen as indistinct sacroiliac joints. A left hip excision arthroplasty had been performed previously for severe joint disease. The right femoral head and acetabulum . . .