Indian J Med Microbiol Close
 

A) The computerized lateral radiograph of the cervical spine in neutral position showing an orthotopic os odontoideum. The ring of the atlas is narrow, with the posterior arch of the atlas being well anterior to the spinolaminar line. There is no AAD. The ventriculoperitoneal shunt tube is visualized. B) In fl exion of the neck, AAD is present with decrease of the dynamic cervical canal diameter between the posteriorly displaced attached part of the odontoid and the posterior arch of the atlas. The posterior arch of atlas has displaced anterior to the spinolaminar line. C) On extension of the neck, there was retrolisthesis of the anterior arch of the atlas-os odontoid complex relative to the body of axis, causing cervical canal compromise. The posterior arch of atlas has displaced posterior to the spinolaminar line

A) The computerized lateral radiograph of the cervical spine in
neutral position showing an orthotopic os odontoideum. The ring of the atlas is narrow, with the posterior arch of the atlas being well anterior to the spinolaminar line. There is no AAD. The ventriculoperitoneal shunt tube is visualized. B) In fl exion of the neck, AAD is present with decrease of the dynamic cervical canal diameter between the posteriorly displaced attached
part of the odontoid and the posterior arch of the atlas. The posterior arch of atlas has displaced anterior to the spinolaminar line. C) On extension of the neck, there was retrolisthesis of the anterior arch of the atlas-os odontoid complex relative to the body of axis, causing cervical canal compromise. The posterior arch of atlas has displaced posterior to the spinolaminar line