A dynamic interbody device for a human spine is provided to stabilize a human spine. In some embodiments, the dynamic interbody device includes a first member and a second member. In some embodiments, dynamic interbody device includes a first member, a second member and a third member. In some embodiments, the dynamic interbody device may include a bridge. The bridge may be used to couple the dynamic interbody device to a posterior stabilization system. In some embodiments, two dynamic interbody devices may be placed in a disc space between vertebrae.