Compression of the dural sac is not necessarily due to spinal cord cervical spondylosis, but may also be caused by radiculopathy, vertebral artery cervical spondylosis, cervical spinal stenosis, and other factors. 1. Spinal cord cervical spondylosis: When the cervical intervertebral disc protrudes posteriorly to the center, it will lead to compression of the outer dura mater of the spinal cord. As the protrusion worsens, it will also compress the spinal cord tissues, resulting in weakness and reduced function of the lower limbs. 2. Nerve root type cervical spondylosis: the cervical nerve roots are wrapped around the dura mater, and degenerative changes in the cervical vertebrae will cause lesions of the surrounding nerve roots, which will lead to compression of the dural sac, causing pain, weakness, numbness and other phenomena. 3. Vertebral artery-type cervical spondylosis: while cervical spine pathology leads to changes in the physiological curvature of the cervical spine, it also tends to lead to hyperplasia of the posterior longitudinal ligament of the cervical spine, which will compress the dural sac and cause pain and weakness. 4. Cervical spinal stenosis: when the cervical spinal canal is severely narrowed, it will compress the surrounding dural sac, which will lead to damage of the spinal cord conduction function, resulting in limb weakness, sensory abnormalities and other symptoms. In conclusion, compression of the dural sac does not necessarily indicate spinal cord cervical spondylosis. In order to find out the cause of the disease, it is recommended to go to the hospital for relevant physical examination and imaging tests.