In a review of 42 cases of degenerative arthritis of the cervical spine and 22 cases of cervical spine trauma with an observed anterior slippage (spondylolisthesis) or posterior slippage (retrolisthesis) of the vertebral bodies of 2 mm or more, characteristic features were observed which allowed distinction between degenerative and traumatic slippage of the cervical spine. In degenerative slippage the shape of the articular facets and width of the facet joint space may remain normal; however, in most cases the articular facets become ground-down with narrowing of the facet joint space and the articular facets themselves becoming thinned or ribbon-like. In traumatic slippage the artucular facets will either be normally shaped or fractured and the facet joint space will be abnormally widened. Plain radiographs will usually allow this distinction to be made; however, in difficult cases polytomography may be required.