[Cinematic study of the cervical spine during flexion-extension movements].

By means of dynamic roentgenographic study (5 to 7 X-rays) of the cervical spine in sagittal plane, the authors were able to define: amplitudes of each intervertebral joints. C4, C5 and C6 are the more mobile levels, position of instant centers of rotation for each intervertebral joint in healthy and pathologic individuals. This method allows a kinematic diagnosis of discopathies.