an artificial spine for use in an expansion of a vertebral canal which comprises an intermediate section having a pair of contacting surfaces in both ends thereof , the contacting surfaces being disposed along each outer end of a pair of divided spines ; an inner side section extending from the intermediate section to between said pair of divided spines and having a width , in a horizontal cross - section thereof , which is gradually reduced in the direction of the vertebral canal ; and an outer side section extending from the intermediate section to a side opposed to said inner side section , the outer side section being disposed out of the divided spaces ; and at least a surface portion of the artificial spine being formed from a biocompatible ceramic material . the artificial spine has an excellent compatibility with the divided spines , and can be easily fixed to the divided spines , without hindering movement of a cervical spine .