The presentation of a patient to a chiropractic office with an undiagnosed C1 burst fracture (Jefferson fracture) secondary to head trauma from a motor vehicle accident is introduced.A 67-yr-old real estate manager suffered from neck pain and stiffness following release from a major metropolitan medical center. Anteroposterior open mouth radiographic examination of the cervical spine revealed 10-mm displacement of the lateral masses of C1 relative to the superior articulating facets of C2, indicating the presence of a C1 burst fracture with possible disruption of the transverse ligament.The patient was transferred by ambulance to a local medical center where a CT scan of the cervical spine and neurosurgical evaluation were obtained. The patient's cervical spine was immobilized in a Philadelphia collar for 3 months. Follow-up radiographic evaluation indicated nonunion of the fracture fragments and the patient was referred for further neurosurgical consultation.The presumption of proper and competent prior medical treatment, without confirmation by radiographic examination and review of records, could have resulted in catastrophic consequences for this patient, had chiropractic manipulation been performed. A history of trauma should be a clear signal to the chiropractic practitioner that they should proceed with caution, regardless of the patient's prior history of examination and treatment.