Sleeping on the back of the head is not good for the cervical spine for the following reasons: First, sleeping on the back of the head can make the neck muscles obviously tense, and there is strain pain, neck muscle strength gradually weakened, cervical spine stability will decline, cervical curvature will be changed, which in the long run can lead to cervical spondylosis, or the original cervical spondylosis is aggravated condition. Secondly, sleeping on the back of the head, the cervical anterior longitudinal ligament excessive tension, cervical intervertebral disc rear excessive extrusion, can cause cervical anterior longitudinal ligament attachment at the bone spurs, cervical intervertebral disc compression of the spinal nerves, caused by the neck pain and so on.