Spinal Hernia: This done by changing the orientation of one of the backrest segments or separating them. Changing the orientation of one segment creates a cavity which is at its greatest in the centre diminishing towards the edges. The position of the cavity can be raised or lowered depending on which segment is inverted and the position of the combined segments. Separating the segments and mounting them independently greatly increases the options for positioning the cavity and creating the appropriate size. <<<back