Cervical spine injury is a significant cause of morbidity and mortality in the traumatized patient. Little of the trauma literature addresses injury to the cervicothoracic junction (C7-T1); we were able to find only two studies that evaluated the incidence of injury in this area. The spinal injury registry of St Joseph's Hospital and Medical Center and Barrow's Neurological Institute in Phoenix, Arizona, was reviewed for cervical spine-injured patients. Of the 397 patients with cervical spine injury admitted between January 1980 and June 1985, 37 (9%) had cervicothoracic junction injury. Documentation of signs and symptoms of neck injury was recorded for each patient. All available lateral cervical spine radiographs were evaluated for indirect evidence of injury through the level of C7 as currently recommended in the trauma literature. Films were reviewed after being masked at the middle of the body of C7 thereby visualizing the C6-C7 junction. The incidence of C7-T1 injury in our cervical spine-injured population was 9%. Nine of the patients (24%) had a depressed level of consciousness and had neurologic examination that was not diagnostic of spinal injury. All of the cervical injuries in these patients were diagnosed by radiographic evaluation alone. We recommend that adequate visualization of the cervical spine through the cervicothoracic junction must be the standard for trauma care.