Diffuse idiopathic skeletal hyperostosis.

The ubiquitous nature of spinal ligamentous calcification in the paleontologic record provides additional support for the suggestion that DISH is a protective phenomenon rather than a musculoskeletal disease, and perhaps represents a normal variant. Clinical assessment of contemporary DISH suggests a protective mechanical effect, paradoxically associated with increased risk of hypertension and cerebrovascular accident. DISH should probably not be considered a satisfactory explanation for back pain, but the presence of spinal ligamentous calcification requires that the patient be assessed for hypertension and that aggressive therapy be instituted for any found.