AOD is an uncommon traumatic injury that can be difficult to diagnose and is frequently missed on initial lateral cervical spinal radiographs. AOD is often associated with severe traumatic brain injuries. Patients who survive AOD injuries often have neurological impairment including lower cranial nerve deficits, unilateral or bilateral weakness, or quadriplegia. Nearly 20% of patients with acute traumatic AOD will have a normal neurological examination on presentation. The lack of localizing physical/neurological examination findings and/or global neurological deficits from severe brain injury may impede/hinder the diagnosis of AOD in patients with normal-appearing initial cervical radiographs. A high index of suspicion must be maintained in order to diagnose AOD. Prevertebral soft tissue swelling on a lateral cervical radiograph or craniocervical subarachnoid hemorrhage on axial CT images have been associated with AOD and should prompt consideration of the diagnosis. Additional imaging including CT and MRI may be required to confirm the diagnosis of AOD if plain radiographs are inadequate.TheCondyle-C1interval as determined onCTimaging has the highest diagnostic sensitivity and sensitivity for AODamong all other radiodiagnostic indicators. All patients with AOD should be treated. Without treatment, nearly all patients developed neurological worsening, many of whom never fully recover. Treatment of AOD with traction is not recommended. Treatment with external immobilization has been used successfully in selected patients but has a high failure rate. Craniocervical fixation and fusion is recommended for the treatment of patients with acute traumatic AOD. © 2013 by the Congress of Neurological Surgeons.