Axis peg fracture (type 3) and atlas lateral mass (type 4) fracture

Case contributed by Craig Hacking
Diagnosis certain

Presentation

MBA.

Patient Data

Age: 25 years
Gender: Male

There is a slightly posteriorly displaced transverse type III fracture of the odontoid process of C2. Associated prevertebral soft tissue swelling. There is widening of the right atlanto-occipital joint and suggestion of an associated fracture of the posterior right lateral mass of C1, best appreciated on the sagittal projection. Bilateral C7 cervical ribs, with the left rib fused to the transverse process which is fractured posteriorly.

Small left apical pneumothorax.

Conclusion:

  • Minimally displaced type III fracture of the odontoid process of C2.
  • Suggestion of an subtle right posterior C1 lateral mass fracture (Gehweiler type 4) with widening of the right atlanto-occipital joint. MRI is recommended.
  • Fractured left C7 transverse process fused to a cervical rib.
  • Small left apical pneumothorax.

Case Discussion

C2 odontoid process fractures should be graded I, II or III (Anderson and D'Alonzo classification) as the grading indicates the risk of non-union and hence the need for operative management.

Always look for upper rib fractures and apical pneumothorax on a C-spine trauma CT.

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