The cervical spine is injured in 3% of major trauma patients. Radiographic clearance for injury must be provided efficiently and accurately. There are numerous choices for clearance that are now in clinical practice: lateral radiograph only, 3-view or 5-view cervical-spine (c-spine) series, flexion-extension radiographs, computed tomography (CT) with multiplanar reformations, and magnetic resonance imaging (MRI). This article reviews the literature on methods of c-spine clearance, and emphasizes the pitfalls of each modality. Although lateral radiographs detect 60% to 80% of c-spine fractures, a significant number of fractures are not visible, even when three views of the spine are obtained. The sensitivity of plain radiographs can be improved by attention to several subtle features, which are discussed. Flexion-extension radiographs in the acute setting have an unacceptably high false-negative and false-positive rate. CT detects 97% to 100% of fractures, but its accuracy in detection of purely ligamentous injuries has not been documented. Furthermore, CT is limited in patients with severe degenerative disease. MRI is highly sensitive in the detection of ligamentous injury, but not all cases of injury may cause instability. MRI is also much less sensitive than CT to fractures of the posterior elements of the spine, and to injuries of the craniocervical junction. The causes of missed cervical spine injury and delayed instability are discussed and shown in this article. An algorithm for the use of advanced imaging is proposed.