Motion of the cervical spine in asymptomatic subjects.

Motion of the cervical spine in asymptomatic individuals has been scarcelyinvestigated. In this study we analyzed the motion of the cervical spine by flexion-extension radiographs in voluntary adults asymptomatic vertebral subjects who hador had not degenerative vertebral changes.Seventy-three subjects, with no previous history of pain in the neck or the upperlimbs, were asked to undergo plain radiographs and active flexion-extensionradiographs of the cervical spine. Twenty-three subjects were excluded from thestudy because their radiographs did not allow reliable measurements. The studygroup consisted of 22 men and 28 women with a mean age of 39 years (range 23 -59 y ) The height of the disc spaces was measured at C2-C3 to C6-C7 and rated asnormal, slight decreased (less than 50%) or markedly decreased (more than 50%).The presence of osteophytes and the severity of arthrosic changes were recorded.The angular and translation motion in the sagittal plane were measured according toPenning's method. Measurements were performed indipendently by three observers.Twenty-two subjects (44%) had degenerative changes of the cervical spine. Theseincluded a reduction of the disc space height at one intervertebral level in 8 cases(16%), at two levels in 5 (10%), and at more than two levels in four (8%), Seven ofthe subjects who had disc disease and 5 who had not, showed anterior and/orposterior osteophytes or arthrosic changes of the cervical spine. In the 17 subjectswith degenerated discs, reduction of the disc height was slight in 14 (82%) andmarked in 3 (18%). The mean angular motion in the 50 subjects under study was, atC2-C3 to C6-C7, 8°a, 15°, 18°, 17® and 17° respectively. In the subjects with slightreduction of a single disc space, the angular motion at the abnormal level wassimilar to that in normal spines. Instead, subjects with degenerated discs at two ormore adjacent levels showed a significant decrease of angular motion at theabnormal levels. The levels above and below the abnormal discs showed no increasein angular motion. Of the 50 subjects examined, 13 (26%) had an anterior translationin flexion radiographs greater than 2 mm at one or more levels.