The main functions of cervical traction are: 1. to limit cervical spine activities, restore cervical spine sequence, release cervical muscle spasm, reduce the inflammatory reaction brought about by instability, in order to reduce local congestion and edema. 2.Increase the vertebral space and intervertebral foramen to reduce its compression on nerve roots. 3.Reduce the pressure in the intervertebral disc, which is conducive to the decompression of the already protruding fibrous tissue, so that the protrusions can be retracted before the formation of adhesions, and release the compression. 4.Drawing away the overlapping small joints or the embedded synovial membrane, reducing the stimulation of the nerve root and vertebral artery by the bone spur of the hooked vertebral joint, so that the inflammatory response can be reduced.