Acute cervicomedullary angle and ventrally compressed brainstem. Herniated of hindbrain, and invaginated clival-atlantoaxial complex
The clivus has a completely horizontal orientation (platybasia). There is mass effect over the brain stem and mild dilation of the lateral and third ventricles is noted. There is arrested cerebellar tonsils posterior to the body of C2 and the opisthion.
Additionally there is partial fusion of C5 and C6 vertebral body.
No evidence of siryngomyelia in the imaged cord.