[Roentgen diagnosis of traumatic instability of the middle and lower cervical spine (C3-C7)].

The problems are discussed that are encountered in diagnosing instability of the middle and lower cervical spine on the basis of conventional radiographs. Two aspects are considered: 11 elementary radiological signs are presented; the corresponding radiological syndromes, their clinical presentations, and the roentgenographic signs are discussed. Both aspects are illustrated by means of appropriate radiographs.