FIGURE 112.34 Graphic illustrations of a normal cervical spinal cord and specific postinjury syndromes A: Brown-Séquard syndrome B: Central cord syndrome C: Anterior artery syndrome D: Complete transection The os odontoideum is an abnormality that may be the result of an occult flexion injury with subsequent incomplete healing and bone resorption ( Fig 112.35 ) It may also represent an overgrowth of the ossiculum terminale, often