Proprioception is the word used to describe the sense of body position and movement.  Of course, if you were to close your eyes and move your arm, you would know exactly where your arm is without having to look at it.  The ability to sense movement and perceive body position is due to receptors in the muscles, tendons and joints, known as mechanoreceptors.  These receptors send information to the brain about joint-position and muscle tension, which enables the brain to make decisions about muscle activation and movement of the body.

In the muscles and facet joints (see diagram 1) of the neck, or cervical spine, there is a high density of mechanoreceptors, suggesting that the brain requires lot of information about neck position, particularly in the upper regions of C1-C3 (see diagram).  The brain uses this information to program muscle tone and protective reflexes in the many muscles of the neck (see diagram) enabling joint stability and preventing degeneration.  The brain also integrates neck proprioception with visual and vestibular information, to enable proper balance, as well as movement of the eyes and head.  Research has shown that impaired neck proprioception correlates with higher levels of neck pain, as well as contributing to symptoms such as dizziness, headaches and visual disorders.