Distraction type injury at the craniocervical junction. Fracture-dislocation through the atlas and involving the atlanto-occipital articulations.
Basion-dens interval is 29 mm. The usual interval is <8.5 mm on CT.
Global reduced attenuation with loss of CSF spaces. There is widespread subarachnoid blood, particularly in the posterior fossa suggestive of traumatic subarachnoid haemorrhage.