Imaging description

Craniovertebral junction (CVJ) injuries are uncommon compared with other cervical spine traumatic injuries but they have a much higher rate of mortality and morbidity. When there is an associated fracture of the occipital condyles, clivus, or C1 vertebra, these injuries are easily identified on CT although plain radiograph diagnosis may be problematic. Some CVJ injuries, however, present with only ligamentous disruption and intact bones, making the diagnosis difficult for those who are not familiar with the normative measurements of the distances between the occiput and C1 (Fig. 86.1) [1].

Two of the CVJ injuries that can present with only ligamentous disruption are atlanto-occipital dissociations (AOD) and atlanto-axial dissociations (AAD) (Figs. 86.2, 86.3). AOD and AAD are extension–distraction type injuries that are associated with rupture of the tectorial membrane, alar ligaments, atlanto-occipital membrane, and the capsular ligaments of the occiput–C1 and C1–C2 joints. AOD and AAD are more common in pediatric populations, associated with high-speed motor vehicle accidents and injury to other body parts, particularly the CNS. The diagnosis is suspected by indirect CT signs and confirmed with MRI.