... to earth's gravity. Perhaps the best way to study the effects of gravity upon the human spine and nervoussystem is to study humans as they actively adapt to envi-ronments where the gravitational ... joint," "afferent,""vestibulocollic," "cervicocollic," and "postural reflexes,""spaceflight," "microgravity," "weightlessness," ... from the year 1970, we searched the MEDLINEdatabase using the following key words and phrases: "pos-ture," "ocular," "vestibular," "cervical facet joint,"...