Severe and moderate head injury can cause misdiagnosis of a spinal cord injury, leading to devastating long-term consequences. The objective of this study is to identify risk factors involving spine trauma and moderate-to-severe brain injury. A prospective study involving 1617 patients admitted in the emergency unit was carried out. Of these patients, 180 with moderate or severe head injury were enrolled. All patients were submitted to three-view spine series X-ray and thin cut axial CT scans for spine trauma investigations. 112 male patients and 78 female patients, whose ages ranged from 11 to 76 years (mean age, 34 years). The most common causes of brain trauma were pedestrians struck by motor vehicles (31.1%), car crashes (27.7%), and falls (25%). Systemic lesions were present in 80 (44.4%) patients and the most common were fractures, and lung and spleen injuries. 52.8% had severe and 47.2% moderate head trauma. Fourteen patients (7.8%) suffered spinal cord injury (12 in cervical spine, one in lumbar, and one thoracic spine). In elderly patients, the presence of associated lesions and Glasgow Coma Scale (GCS) < 9 were statistically significant as risk factors (P < 0.05) for spine injury. Spinal cord injury related to moderate and severe brain trauma usually affects the cervical spine. The incidence of spinal lesions and GCS < 9 points were related to greater incidence of spinal cord injury.