Neck pain. Evaluate spine stability. Evaluation the cervicothoracic junction is limited on the lateral views due to overlying anatomy. There is deformity of the odontoid process of C2 as well as the anterior arch of C1, as noted in the report of the prior MRI examination. Although the bony margins of the dens/C1 complex are in part difficult to define, I suspect that there is approximately 3 mm of anterior subluxation of the dens relative to the body of C2. Furthermore, the degree of subluxation appears to increase to approximately 6 mm with flexion. A minimal (1 mm) anterolisthesis of C4 is also elicited on flexion, but I otherwise see no frank instability of the cervical spine. Intervertebral disc spaces are preserved.
Deformity of the odontoid process of C2 and anterior arch of C1 is better appreciated on prior MRI. There appears to be anterior subluxation of the dens-C1 complex relative to the body of C2 as described above.