Calcification of the Posterior Longitudinal Ligament of the Spine among Japanese

Eight cases of calcification of the longitudinal ligament are reported. This condition can cause severe neurological symptoms, but diagnosis is not difficult if the spine is radiographed. Although the etiology is not known, the relationship to spondylosis deformans is described. The reason why this is seen rather frequently among Japanese is not clear. Some unknown factors, possibly dietary, may influence the deposition of calcium or bone in the posterior longitudinal ligament.