Fig. 1.

(A) Because of reduced spinal mobility, the patient could not touch the mattress with the back of his head while lying down. (B–D) Radiography of the spine showing osteophytes on the anterior and lateral aspects of the vertebral columns with preserved intervertebral disc spaces. (E) Radiography of the cervical spine showing degeneration of the vertebral bodies with bone spurs. No upper airway obstruction owing to diffuse idiopathic skeletal hyperostosis lesions are observed. (F, G) Chest computed tomography showing longitudinal ossification of the anterior longitudinal ligament and hyperostosis of the thoracic costovertebral joints.