Introduction: The aim of this review was to investigate whether Flexion/Extension (F/E) radiography adds diagnostic value to CT or MRI in the detection of cervical spine ligamentous injury and/or clinically significant cervical spine instability of blunt trauma patients. Methods: A systematic search of literature was done in Pubmed, Embase and Cochrane Library databases. Primary outcome was sensitivity and specificity of F/E radiography. Secondary outcomes were the positive predicting value (PPV) and negative predicting value (NPV) (with CT or MRI as reference tests due to the heterogeneity of the included studies) of each modality and the quality of F/E radiography. Results: F/E radiography was overall regarded to be inferior to CT or MRI in the detection of ligamentous injury. This was reflected by the high specificity and NPV for CT with F/E as reference test (ranging from 97 to 100% and 99 to 100% respectively) and the ambiguous results for F/E radiography with MRI as its reference test (0-98% and 0-83% for specificity and NPV respectively). Image quality of F/E radiography was reported to have 31 to 70% adequacy, except in two studies which reported an adequacy of respectively 4 and 97%. Conclusion: This systematic review of the literature shows that F/E radiography adds little diagnostic value to the evaluation of blunt trauma patients compared to CT and MRI, especially in those cases where CT or MRI show no indication of ligamentous injury.