Associations
- Morquios
- Spondyloepiphyseal dysplasia
- Achondroplasia
- Downs- 25% have instability
- Pharyngeal infection in the normal child ( = Grisels syndrome)- due to hyperaemia causing demineralisation of the attachment of the transverse ligament to its attachment to the anterior arch of the atlas
- rotatory subluxation or anterior subluxation
Atlanto dens interval
- more than 5mm = instability
- more than10mm = indication for surgery