Every normal person has a cervical vertebra that belongs to him or her, which is located in the middle of the back of the neck under our head. Under normal circumstances, the cervical spine consists of seven cervical vertebrae, six intervertebral discs (no discs between the 1st and 2nd cervical vertebrae) and their respective ligaments. It is connected to the skull and the first thoracic vertebrae, surrounded by the neck muscles, blood vessels, nerves and skin, commonly known as the “neck” or “neck”. It is with the help of the cervical vertebrae that the human body completes the function of rotating the head at all angles. Under normal circumstances, the human cervical spine has a forward curvature, called physiological pronation. The formation of the cervical curvature is maintained by the thick front and thin back of the cervical 4 to 5 intervertebral discs, which is required by human physiology. It can enhance the elasticity of the cervical spine, play a certain role in cushioning oscillations and prevent brain damage. At the same time, it is also a normal anatomical and physiological need for the cervical spinal cord, nerves, blood vessels and other important tissues. The physiological pronation is just like the open sail of a sailboat, and the muscles in front and behind the cervical spine are just like the cables on both sides of the sail, which work together to maintain the stability of the cervical spine and normal flexion and extension, rotation and other functions. In any case, people are most comfortable to maintain this cervical spine physiological foreshortening. People in sleep is no exception, and this requires a pillow to complete the normal cervical spine physiological convexity to maintain the role. In order to explain the reasoning, we might as well compare the cervical spine with normal physiological curvature to a curved bow, curved bow to rely on the bowstring to maintain the “bow bend” state, the posterior cervical muscle groups just like the bowstring to maintain the normal physiological curvature of the cervical spine. There is no doubt that after a day of exertion, our posterior cervical muscles will be fatigued due to the tension state throughout the day. When the human body sleeps, if there is an “external force” that can replace the tension of the “bowstring” (posterior cervical muscles), then it will make the posterior cervical muscles do not have to maintain the cervical curvature and get sufficient rest, while the human cervical spine does not lose its normal physiological curvature. This is conducive to the skin of the neck, muscles, ligaments, intervertebral discs, intervertebral joints, as well as through the neck trachea, esophagus, nerves and other tissues and organs to relax and rest with the whole body during sleep, thereby delaying the degeneration of the cervical muscle, to prevent the occurrence of cervical spondylosis. Science shows that adults should contribute to a healthy sleep time of not less than 8 hours a day, it can be seen that, in a person’s life, about a third of the time is spent in sleep. It can be seen that when sleeping, the pillow is the human body to maintain the physiological bending of the cervical spine needs, which is not only to protect the joints of the neck, the basic conditions for adequate rest of the muscles, but also one of the key factors in the prevention and treatment of cervical strain injury.