The mechanism of ossification of spinal ligamens : espically on the morpho;ogical studies of the spinal ligaments and its cultured cells

In order to know the mechanism of ossification of the spinal ligament, the ossified ligaments and their cultured cells were investigated morphologically by use of transmission electron microscopy. The results were as follows : 1. The cells in the ossified ligaments chiefly consisted of osteogenic undifferentiated mesenchymal cells, while the cells in the non-ossified ligaments chiefly consisted of fibroblast. 2. In the areas close to the ossified lesions, the arrangment of collagen fibers was irregular, the cells in the ligaments showed degenerative changes and contained chondrocytes. 3. In this areas, the matrix vesicle calcification precedes the ossification of the ligaments. 4. The ossification of the spinal ligaments occurs based on the changes of the constitution of the cells in the ligaments, and the systemic and local factors promote its process.