IMPORTANT: We currently have a number of bugs related to image cropping and are actively trying to resolve them. In the meantime, we have disabled cropping. Apologies for any inconvenience. Stay informed: radiopaedia.org/chat

Bilateral atlanto-occipital assimilation

Case contributed by Henry Knipe
Diagnosis certain

Presentation

Alleged assault.

Patient Data

Age: 55 years
Gender: Female

Cervical spine

ct

Bilateral atlanto-occipital assimilation. Congenital C2/3 fusion. Well-corticated calcification at anterior C4/5 disc space appear chronic and are degenerative in nature. No acute cervical spine fracture or malalignment demonstrated. Prevertebral soft tissues are within normal limits. Mild multilevel degenerative change with posterior disc bulges at C3/4, C4/5 and C5/6 indenting the thecal sac.

Case Discussion

This case demonstrates partial atlanto-occipital assimilation, with the posterior arch of C1 not fully fused and still identifiable. Atlanto-occipital assimilation is often asymptomatic (as in this case) and represents a transitional vertebrae. There is also congenital C2/3 fusion, which is often associated. 

How to use cases

You can use Radiopaedia cases in a variety of ways to help you learn and teach.

Creating your own cases is easy.

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.