It has been suggested that man stood upright too soon in his evolution; that the effect of balancing on two feet instead of standing squarely on four strains bones, organs and nerves. However that may be, the spine in two footed creatures has had to assume the additional function of keeping the body upright. In this it fights a constant battle against the forces of ​c​entral gravity which, while holding us to the earth’s surface, also exert a downward pull on the whole organism​.