ankylosing spondylitis

noun

: a chronic inflammatory disease that affects the spine and sacroiliac joints and often other joints (as of the shoulder) and that is marked by pain and stiffness

Note: Ankylosing spondylitis is more common in males, with symptoms typically appearing during the late teens through the early forties. In some cases bones may fuse and cause parts of the spine to become inflexible.

Although the disease has a predilection for the axial skeleton, the peripheral joints are commonly affected; in patients with long-standing ankylosing spondylitis, the shoulders are involved in approximately 33 percent of cases.

—Medical Radiography & Photography

Although ankylosing spondylitis has been considered a relatively benign form of arthritis, a recent study showed that the rates of pain and disability among patients with ankylosing spondylitis were similar to the rates among those with rheumatoid arthritis.

—Jennifer D. Gorman, The New England Journal of Medicine

called also Marie-Strümpell disease, rheumatoid spondylitis