Currently, with people's increased awareness of health, the harmfulness of the cervical spondylosis is seen more and more.  If the cervical vertebra is in an abnormal stable state of extreme anteflexion for a long period of time, the cervical vertebra would be harmed, and such harmfulness is dozens of times severer than that caused by viewing a computer.  Currently, however, there is no scheme to perform a quantitative measurement on a movement of the cervical vertebra. 
Accordingly, there is needed a scheme capable of measuring a movement of the cervical vertebra.