1. Background: Patients with Crowned dens syndrome typically present with severe neck pain and have calcium deposits around the odontoid process of the axis on radiographs

2. Non-achondroplastic dwarfs may have an associated odontoid dysplasia and if the neck is placed in flexion there is a potential risk of spinal cord damage.

3. Basilar invagination, also called Basilar impression, is a congenital or acquired craniocervical junction abnormality where the tip of the odontoid process projects above the foramen magnum.

4. The imageology showed that forward atlantoaxial subluxation was verified in 16 cases, which was related with erosive osteoclasia in the atlantoaxial, atlanto-odontoid and atlanto-occipital joints.