[Degenerative blockbuilding between the 2d and 3d cervical vertebrae].

Two from 59 anatomical samples of the upper cervical spine show an osseous fusion of the axis and the third cervical vertebra. Moreover, a non-osseous but very rigid union between the second and the third cervical vertebrae is observed in five cases. Generally the fusions seem to be caused by degenerative processes. For these, a more horizontal or vertical orientation of the articular facets of the vertebral joints is important. The failure of development of the dorsal part of the axis' transverse process promotes degenerative alterations.