Influence of Cervical and Upper Thoracic Spine Dynamics on Head Translational Movement of 15 mm in the Supine Position

Abstract

[Purpose] To clarify the contributions of the thoracic and cervical spines to translational head movements. [Subjects and Methods] A kinetic analysis of the rotational angles of each vertebra from C3 to T5 in anterior and posterior translational head movements of 12 healthy females in the supine position was performed using MRI. [Results] It was found that translational head movements of 15 mm elicited movements in the thoracic vertebrae. Furthermore, some subjects showed ventral movement by all of the vertebrae from C3 to T5, while other subjects showed ventral to dorsal movement in either the cervical vertebrae or some of the vertebrae to T5. [Conclusion] In the cervical and thoracic spine, there is a point where the curvature changes from lordosis to kyphosis, and our results, showing differences in the subjects’ vertebral movements, confirm that there are individual differences in this point. This suggests the necessity of considering not only cervical vertebrae, but also thoracic vertebrae when making translational head movements.