活动范围被认为是定量评价环枢关节不稳的最好指标,但还没有动态量化的运动学指标。临床上环枢关节不稳被定义为颈椎屈伸侧位片上齿突前间隙大于3mm,该项指标为静态指标,不足以代表环枢椎的不稳。连续的动态分析非常重要,X线活动摄影术已经被用于分析在体脊椎的各种运动方式,但准确的动态定量测定环枢关节不稳的方法还未建立。研究采用X线活动摄影术以比较健康与不稳定的环枢关节 The range of activities is considered as the best indicator to quantitatively evaluate the instability of the cricoid joints, but there are no kinematic indexes for dynamic quantification. Clinic clinical pivot instability is defined as cervical spine flexion and extension of lateral odontoid anterior gap greater than 3mm, the index for the static indicators, not enough to represent the instability of the pivot axis. Continuous dynamic analysis is very important. X-ray photography has been used to analyze various movement patterns in the vertebral body. However, an accurate and dynamic method for quantitatively determining the instability of the pivot has not been established yet. Study using X-ray photography to compare the health and instability of the Central Axis