The effectiveness of five cervical orthoses in restricting cervical
motion was evaluated quantitatively in normal subjects using roentgenograms
and overhead photographs made at the extremes of three planes of motion,
while the effectiveness of the halo with a plastic body-vest was studied in
seven patients with cervical fractures or local fusions. Flexion and
extension were measured at each cervical intervertebral joint and combined
cervical motion was measured for rotation and lateral bending. The best
conventional braces restricted only 45 per cent of flexion-extension at the
atlanto-axial joint; the halo restricted 75 per cent. The conventional
braces were more effective in the middle and lower portions of the cervical
spine. The results may prove to be useful guidelines for the selection of
an appropriate orthosis to control motion in different planes and at
different levels of the spine.