Thoracic ligamentous ossification is common in Asians, especially in Japanese, and its incidence is 5-25%. The disease is a degenerative disease, with a high incidence between 50 and 70 years of age, and a trend of increasing incidence with age, with a higher incidence in men than in women, with a male to female ratio of about 2:1. The disease is common in the lower thoracic segment, accounting for about 67%, the upper thoracic segment 6%, and the middle thoracic segment less. The etiology of the disease is still unclear, and most scholars believe that it may be related to chronic injury degeneration, inflammation and metabolic factors. Studies have shown that ossification of the ligamentum flavum is an endochondral ossification process. The lesion starts from the dural surface, with early disorganization of the fibrous structure, reduction of elastic fibers, and massive proliferation, swelling, and mucus-like degeneration of collagen fibers; it further develops into chondrogenesis of undifferentiated mesenchymal cells in the ligamentum flavum tissue to form fibrochondrocytes; finally, calcification and ossification of calcium salt crystals deposition. The ossified ligamentum flavum tends to have four migratory zones from superficial to deep: ligamentous zone, cartilage-like zone, calcified cartilage-like zone, and ossified zone.