The ratio between the dia-meter of vertebral canal and that of duramater capsule in the sagittal directionis 1 to 0.73 at the cervical segment level, 1 to 0.68 at the thoracic segmentlevel and 1 to 0.60 at the lumbar segment level.

• 椎管与硬膜囊的比值(矢状径)颈段为1:0.；73；胸段1:0