Fig. 14

Dystopic os odontoideum in a 19 year old: Sagittal (a), coronal (b) and axial (c) images from a non-contrast CT in a 19 year old demonstrate a well-corticated ossific density along the superior margin of the dens (marked by asterisks on images a, b and c). The dens itself is relatively small with a foreshortened base (block arrow on b). Note that the os odontoideum is located somewhat posterior to the C2 body and is therefore not in its expected anatomic location