Dynamic cervical spine radiography (CSR) is used to detect ligamentous instability. We investigated the ED use of dynamic CSR through a retrospective descriptive review using a convenience sample study design at a university emergency department. Adult blunt trauma patients with static (lateral, AP, odontoid) and dynamic (flex, extend) CSR participated. 451 patients (52% male with mean age of 33.6 years) met entry criteria. Injury mechanisms were 74% MVA, 12% fall, 8% direct trauma, and 6% other. Indications for dynamic CSR were 100% traumatic mechanism, 86% neck pain, 70% midline neck tenderness, and 18% abnormal static CSR. Static CSR were normal in 372, 5 of which had abnormal dynamic CSR (5 cervical contour line disruption [CCLD], 2 posterior element abnormality [PEA]); of these 5 patients, none required invasive stabilization. Static CSR were abnormal in 79 patients (38 CCLD, 30 lordotic curve reversal, 17 PEA, 4 soft tissue swelling) of which 16 had abnormal dynamic CSR (9 increased CCLD, 4 PEA, and 4 fracture); of these 16 patients, 4 required invasive stabilization. Final diagnoses were 428 cervical soft tissue injury, 11 subluxation, 8 fracture, 2 fracture-subluxation, and 2 spinal cord injury without radiographic abnormality. Spine consultation was made in 12%. Stabilization therapy was required: 21 soft collar, 4 surgical, 3 halo-device, and 5 other. No complications of dynamic CSR were noted. The blunt trauma patient with neck complaints and an abnormal static CSR was more likely to have an abnormal dynamic CSR demonstrating a cervical injury requiring stabilization compared to patients with normal static CSR.