Degenerative changes of the cervical spine Degenerative changes of the cervical spine are the main cause of the development of cervical spondylosis, of which the degeneration of the intervertebral disc is particularly important and is the first factor in the degeneration of the structures of the cervical spine, from which a series of pathological anatomy and pathophysiological changes of cervical spondylosis evolve. (1) Degeneration of the intervertebral disc: When degeneration of the intervertebral disc begins to occur, it loses its normal function due to morphological changes, which in turn affects or disrupts the biomechanical balance of the cervical spine motion segments and produces a series of changes in each relevant structure. Therefore, degeneration of the cervical intervertebral disc is the main factor in the occurrence and development of cervical spondylosis. (2) Emergence of the ligament-disc gap and hematoma formation: This process is crucial to the occurrence and pathogenesis of cervical spondylosis and is the pathological anatomical basis for its progression from cervical disc disease to osteopathic cervical spondylosis. In fact, in the early stages of cervical spondylosis, the degeneration of the intervertebral disc not only causes the displacement of the dehydrated and sclerotic nucleus pulposus to the posterior or anterior part of the vertebral joint, but also causes the separation of the ligament and periosteum from the peripheral cortical bone of the vertebral body while increasing the local pressure, and the degeneration of the intervertebral disc itself can also cause the loosening and abnormal movement of the intervertebral joint, which further increases the tearing of the ligament and periosteum. Tearing of the ligament and periosteum is exacerbated and the formation of the ligament-disc gap is accelerated. Ligamentous-disc interstitial hematomas are formed after subligamentous separation of the posterior aspect of the vertebral space because of local microvascular tears and hemorrhage. (3) Bone spur formation at the vertebral body margin: With the formation of a hematoma in the subligamentous space, fibroblasts become active and gradually grow into the hematoma, gradually replacing it with granulation tissue. As the hematoma mechanizes, ossifies and deposits calcium salts, it eventually forms a bone flab that protrudes toward the vertebral canal or toward the anterior edge of the vertebral body. (4) Degeneration of other parts of the cervical spine: degeneration of the cervical spine is not limited to the intervertebral disc and the adjacent vertebral body edges and hook vertebral joints, but should also include: ① small joints Mostly degeneration occurs after intervertebral disc degeneration resulting in intervertebral body joint instability and abnormal activity. The ligamentum flavum mostly begins to degenerate on the basis of the degeneration of the first two. In the early stage, the ligament is lax and gradually becomes hypertrophic and thickens and protrudes into the spinal canal. In later stages, calcification or ossification may occur. (3) The degeneration of the anterior longitudinal ligament and posterior longitudinal ligament is mainly manifested by fibrous hyperplasia and sclerosis of the ligament itself, and later calcification or ossification is formed and is consistent with the diseased vertebral segment. (5) Reduction of the sagittal diameter and volume of the spinal canal: Due to the aforementioned causes, the internal volume of the spinal canal is reduced, mainly due to the posterior nucleus pulposus, the invagination of the posterior longitudinal ligament and ligamentum flavum, and the loosening and hyperplasia of the leptomeningeal joint and small joints, which are secondary factors that cause the reduction of the internal volume of the spinal canal and also reduce the sagittal diameter of the spinal canal, thus constituting one of the direct causes of irritation or compression of the spinal cord and spinal nerve roots. At this time, if there are other limited pathogenic factors. For example, nucleus pulposus prolapse, traumatic displacement of vertebral segments, bone spur formation and other occupational factors can cause or aggravate the symptoms of neurological involvement. 2, developmental cervical spinal stenosis In recent years, it has been clear that the internal diameter of the cervical spinal canal, especially the sagittal diameter, has a very close relationship not only to the occurrence and development of cervical spondylosis, but also to the diagnosis, treatment, selection of surgical methods and prognosis of cervical spondylosis. Some people have severe cervical degeneration and significant bone growth, but do not develop the disease, mainly because the sagittal diameter of the cervical spinal canal is wide and there is a large compensatory gap in the spinal canal. In some patients, the cervical degeneration is not very serious, but the symptoms appear early and are more serious. 3, chronic strain injury Chronic strain injury refers to a variety of overlimiting activities that exceed the maximum normal physiological range of activity or the local tolerable hourly value. Because it is different from obvious trauma or accidents in life and work, it is easy to be ignored, but it is directly related to the occurrence, development, treatment and prognosis of cervical spondylosis. This kind of strain and cause mainly from the following three situations: (1) bad sleep position: bad sleep position because of its long duration and in the brain at rest can not be adjusted in time, it is bound to cause the paravertebral muscles, ligaments and joints of the balance disorder. (2) Improper work posture: A large number of statistical materials show that the incidence of cervical spondylosis is particularly high in certain workloads, not high intensity, but in a seated position, especially in low head workers, including domestic workers, embroidery workers, office workers, typing scribes, assembly workers on the instrument assembly line, etc. (3) Inappropriate physical exercise: normal physical exercise helps health, but activities or exercises that exceed the neck endurance, such as inversion or somersault with the head and neck as weight-bearing support points, can increase the load on the cervical spine, especially in the absence of proper guidance. 4, congenital deformity of the cervical spine In the health examination of the cervical spine of normal people or for comparative research film, it is often found that the cervical spine segment can have various abnormalities, of which the obvious deformity of the skeleton accounts for about 5%. However, in contrast to patients with cervical spondylosis, the number of deformities of the cervical spine in the latter is about double that of normal people.