Lateral flexion view of the cervical spine (left) shows a normal relationship of the occipital condyles to the articular facets of the atlas. The atlanto dental interval is also normal. Lateral extension view of the cervical spine (right) shows posterior displacement of the occipital condyles in relation to the articular facets of the atlas. There is posterior positioning of Wackenheim line and retrolisthesis of the C3 on C4 vertebral body. The atlanto dental interval remains normal.
