The segmental motion of lower cervical vertebrae of 26 patients with cervical spondylitis were observed dynamically through digital video-fluoroscopic system.A significant decrease of the lower cervical motion was found in all patients as compared with normal control.Although the limitatoin of motion mainly occurred at the degenerative level,alteration in the range and mode of motion was shown over the whole cervieal spine,resulting disturbance of its physical stress distri bution and aggravation of the degenerative change of the segment.