A herniated disc is a condition experienced by many people, and is especially common in L4-L5, L5-S1. L4-L5 herniations account for 10-20% of all lumbar disc herniations, while L5-S1 accounts for about 50% of all lumbar disc herniations. Therefore, do we need to think about why the discs at L4-L5, L5-S1 are frequently herniated? The reason is that the closer the disc is to the sacrum, the more vertebrae above the corresponding disc, the more significant the weight it bears, and thus the greater the force on the disc the closer it is to the sacral area. Assuming that at the L5,S1 level, the spine bears 2/3 of the weight of the trunk, then the discs need to bear nearly half of the weight. To this is added the tensile stress exerted by the paraspinal muscles to maintain the trunk in an upright position. If the compressive stress is loaded, then violence is applied. For example, if one suddenly lifts a heavy object and gets up, the lowermost disc may be subjected to more compressive stress than it can withstand, especially in the elderly population. There is also a lot of variation in the discs themselves, and damaged discs can vary more when subjected to the same load. The degree of decline in disc thickness varies between healthy and pathologic states. A healthy disc at rest will be compressed by 1.4 mm and expand to the sides if it is subjected to 100 kg of weight. A diseased disc subjected to the same load is compressed by 2 mm and does not regain its initial height even after the pressure load is removed. Disc thickness varies according to its position in the spine: the thickest disc is 9 mm in the lumbar spine, 5 mm in the thoracic spine, and 3 mm in the cervical spine, but more important than the absolute value of disc thickness is the ratio of the disc to the height of the corresponding vertebral body. In fact, this ratio indicates the mobility of a particular vertebral segment. The greater the ratio, the greater the mobility of the corresponding vertebral segment. Thus, in descending order, the cervical spine is the most mobile, with a ratio of 2:5 between disc and vertebral body heights; the lumbar spine is slightly less mobile, with a ratio of 1:3 between disc and vertebral body heights; and the thoracic spine is the least mobile, with a ratio of 1:5 between disc and vertebral body heights. Progressive flattening of the disc has an effect on the synovial joint. At normal disc height, the cartilage of the synovial joints is normally aligned, and the upper and lower synovial joint gaps are straight and regular. In the case of a flattened disc, the synovial joint is affected and, in general, an opening is created in the vertebral space towards the posterior. In the long run, this deformation of the synovial joint is a major factor in spinal osteoarthritis. Thus, a herniated disc may not only only compress the nerves, but also cause changes in the spine itself, altering the structure of the spine. Thus, a herniated disc affects the body as a whole, changing the overall structure and causing some functional impairment.