Genetic Mapping of Ossification of the Posterior Longitudinal Ligament of the Spine  Hiroaki Koga, Takashi Sakou, Eiji Taketomi, Kyouji Hayashi, Takuya Numasawa, Seiko Harata, Kazunori Yone, Shunji Matsunaga, Brith Otterud, Ituro Inoue, Mark Leppert  The American Journal of Human Genetics  Volume 62, Issue 6, Pages 1460-1467 (June 1998) DOI: 10.1086/301868 Copyright © 1998 The American Society of Human Genetics Terms and Conditions

Figure 1 Radiological and histologic findings for OPLL. a, X-ray tomogram of the cervical spine from a typical OPLL subject. The heterotopic ossification of the posterior longitudinal ligament is observed between C3 and C6 (arrows). The patient showed myelopathy in upper and lower limbs, which was due to the compression of the spinal cord. b, Schematic drawing of x-ray radiogram findings. c, MRI, which clearly shows compression of the spinal cord (arrowhead). d, Typical histologic examination from an autopsy case with OPLL. The sagittal section of C3–C6 was stained with hematoxylin-eosin (magnification ×28). o = ossified tissue; cz = calcified zone; and c = cartilage tissue. The American Journal of Human Genetics 1998 62, 1460-1467DOI: (10.1086/301868) Copyright © 1998 The American Society of Human Genetics Terms and Conditions