The first cervical vertebra is also called the atlas, the second cervical vertebra is also called the cardinal vertebra, and the seventh cervical vertebra is also called the lordosis. The first and second cervical vertebrae are together called the upper cervical vertebrae, and the third to seventh cervical vertebrae are together called the lower cervical vertebrae. The upper cervical vertebrae and the lower cervical vertebrae have the following differences: different anatomical patterns: the upper cervical vertebrae have special patterns, and the lower cervical vertebrae have roughly similar patterns. The lower cervical vertebrae have typical vertebral bodies, arches, transverse processes, articular processes, and spinous processes, while the atlantoaxial vertebrae in the upper cervical vertebrae have no vertebral bodies and spinous processes and are annular in shape, with a finger-like dentition extending above the vertebral body of the cardinal vertebrae, forming the atlantoaxial joint with the back of the anterior arch of the atlantoaxial vertebrae. In addition, the spinal canal of the upper cervical spine is wider than that of the lower cervical spine. The proportional contribution to head and neck activity is different: forward and backward head and neck flexion occurs mainly between the atlantoaxial and occipital vertebrae, and left and right head and neck rotation occurs mainly between the atlantoaxial and pivotal vertebrae. In other words, the two vertebrae of the upper cervical spine are responsible for approximately 50% of the range of motion of the cervical spine, with an average of 25% per vertebra, while the five vertebrae of the lower cervical spine are responsible for approximately 50% of the range of motion of the cervical spine, with an average of 10% per vertebra. The chance of acute injury is different: because the upper cervical spine is more mobile than the lower cervical spine, acute injury to the upper cervical spine is also more common than injury to the lower cervical spine. When the upper cervical spine is injured, either the corresponding cervical spinal cord is not involved and the patient’s neurological symptoms are mild, or the heartbeat and respiratory center in the corresponding cervical spinal cord is damaged at the same time and the patient dies immediately; the lower cervical spine has a narrow spinal canal and no heartbeat and respiratory center in the corresponding spinal cord, so when the lower cervical spine is injured, the cervical spinal cord is more likely to be involved When the lower cervical spine is injured, the cervical spinal cord is more likely to be involved, resulting in paralysis, while the patient’s life can often be saved. The lower cervical spine is more susceptible to degeneration than the upper cervical spine: this is because the apex of the physiological curvature of the cervical spine is located in the lower cervical spine, which is where the stress is concentrated and is therefore susceptible to repeated minor injuries that can lead to disc degeneration and other secondary pathological changes. Cervical disc herniation is also found clinically in cervical discs 3-4, 4-5 and 5-6, especially in cervical discs 4-5.