The literature of the last few months abounds with the reports of a morbid condition that has been variously designated stiffness of the spinal column, chronic, progressive rigidity of the spinal column with ankylosis, ankylotic rigidity of the spinal column, ankylosing inflammation of the spinal column and of the large joints of the extremities, chronic ankylosing spondylitis, deforming spondylitis, spinal arthritis deformans, and rhizomelic spondylosis.
The disorder is characterized essentially by increased posterior curvature, with lessened mobility, of the spinal column, often without, but sometimes with nerve-root symptoms, and. involvement also of other joints, particularly the large ones of the trunk. The fundamental lesion in the majority of cases is believed to consist in a proliferative and rarefying inflammatory process involving the vertebræ, the discs between, and the ligaments uniting, them. In some instances there is probably also meningitis, sometimes primary and sometimes associated or secondary. It appears that the