The plain radiographs, lateral view of the case 2 showed the AAD feature with slightly retropulsed os odontoideum over C2 body proper (black arrow), which was untowardly stabilized by cortical rim connection with ventral portion of the C3 vertebra (white arrow). Note the decreased anterior-posterior diameter of the vertebral bodies at the fused C2, C3, as well as C4 levels as compared with the lower subaxial cervical bodies.