Atlanto-occipital dislocation with marked compression of the cervical medullary junction between the opisthion (posterior margin of the foramen magnum) and the dens and the overlying ascending band of the cruciform ligament. This is associated with extensive increased T2 signal (from C1/2 to the brainstem) and haemorrhage within the cord and in the surrounding subarachnoid space. There is disruption of the atlanto-occipital ligament and atlantoaxial membrane posteriorly at C0/1 and C1/2 respectively as well as disruption of the alar ligaments and apical ligaments of the dens.
The theca is disrupted, with a high volume CSF leak seen within the epidural space with collapse of the theca surrounding the cervical cord. The cervical cord is unremarkable from the level of C2 down to upper thoracic cord. The discs, anterior and posterior longitudinal ligaments, ligamentum flavum, and interspinous ligaments are intact from C2/C3 down to the upper thoracic spine. Widespread muscular high T2 signal is demonstrated in the posterior and lateral muscles bilaterally, more so on the right. Normal flow voids are demonstrated within the vertebral arteries, and parts of the carotids that are visualised.