PMC2763064_01
Lateral radiograph showing atlanto-occipital dissociation (more than 12 mm between the basion and dens with a space clearly visible between the cranium and C1). The radiograph demonstrates extensive fusion throughout the cervical spine of both the anterior and posterior elements. Note the extensive fusion of the vertebral bodies of C2/3-4 and the total fusion of the spinous processes of C2-6. Also, note the detached os terminale (arrow)
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A lateral craniocervical radiograph showed that, throughout the cervical spine, there was extensive fusion of both the anterior and posterior elements in association with occipito-vertebral dissociation (arrow) (Figure 1).
Sagittal MRI imaging revealing discontinuity of the cervical ligaments. Note the disruption of the anterior atlanto-occipital ligament, which connects the lower anterior clivus with the anterior aspect of the body of C2, as visualized by the superior continuation of the anterior longitudinal ligament. In addition, disruption of the anterior longitudinal ligament is evident (arrow-b). Note the dislocated atlas (arrow-c) and compression of the dura mater space. Line (d) represents the Wachenheim-clivus line (a method to evaluate craniocervical abnormalities). The line is drawn along the posterior aspect of the clivus, toward the odontoid process (OP). In normal subjects, the line is tangential to the posterior aspect of the OP. In contrast, in our patient, this line intersects the anterior aspect of the OP
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MRI imaging revealed increased discontinuity/disruption of the ligaments effectively causing the observed occipito-vertebral dissociation (Figure 2).