Prevertebral soft-tissue swelling as a sign of undisplaced fracture of the odontoid process.

Marked evanescent swelling of the prevertebral soft tissues has been found in 2 patients with undisplaced fractures of the odontoid process. In one patient the significance of the swelling was appreciated only in retrospect and after shift had occurred at the fracture site. The experience gained from this patient alerted the radiologist and the clinician so that any further damage could be averted in the second patient. All patients with head injuries require radiography of the cervical spine. Soft-tissue swelling anterior to the atlas should be viewed in a serious light.