ABSTRACT
I ANATOMY AND PATHOMECHANICS While the atlantoaxial joint and subaxial spine contribute equally to rotation, most of the flexion and extension in the cervical spine occurs from C3 to C7. Up to 17 degrees of sagittal plane motion occur at individual motion segments of the subaxial spine. Coronal plane motion ranges from 4 to 11 degrees per motion segment in this region (1). The anterior two-thirds of the vertebral body, in concert with the anterior longitudinal ligament and annulus fibrosis, act as a tension band-limiting extension. Posteriorly, the supraspinous and interspinous ligaments, the ligamentum flavum, and the facet capsules resist flexion (2).
