Growth of the cervical spine with special reference to its lordosis and mobility.

Study Design. The cervical spine of the healthy Japanese children aged between 1 year and 18 years was radiographically examined. Objectives. To examine the correlation between growth of the cervical vertebral body and the facet joint and the development of the cervical lordosis and intervertebral motion. Summary of Background Data. Although the growth of body height and facet angle have been well documented, their correlation with curvature or mobility has not been elucidated. Methods. We evaluated plain lateral radiographs of 180 boys and 180 girls regarding diameters and central heights of the cervical vertebra, the anterior and posterior vertebral height ratio, body height index, the facet joint angles, and tilting and sliding motions. Cervical lenght as the summation of the central height from C3 to C7 and the cervical lordosis angle (C3-C7 angle) were also measured. Results. The mean C3-C7 angle and body height index gradually decreased until 9 years of age and then increased. The C3-C7 angle showed a significant correlation with cervical lenght, body height index, and facet joint angles before 9 years of age, and with cervical lenght and body height index after 9 years of age but not with facet joint angles. Facet joint angle decreased until 10 years of age and remained almost unchanged thereafter. Total sliding showed a significant age-related decrease and showed a significant correlation with facet joint angle. Conclusion. Although the lordosis angle showed a significant correlation with the other values, cervical lenght, body height index, and facet joint angle, the determinants of the lordosis could not be elucidate in the present study. As for the mobility of the cervical spine, changes of tilting motion were small, whereas changes of sliding motion were restricted by the change of orientation of the facet joints.