Hyperextension strain or "whiplash" injuries to the cervical spine.

PURPOSE: To define "whiplash" radiologically.

MATERIAL AND METHODS: A full cervical spine radiographic series (including flexion and extension views) was reviewed in 40 patients with clinically proven "whiplash" injuries and compared to the radiographs in 105 normal controls. The level and degree of kinking or kyphosis, subluxation, and the difference in the amount of fanning between spinous processes on flexion and extension films were measured in each patient.

RESULTS: Localized kinking greater than 10 degrees and over 12 mm of fanning, often occurring at the level below the kinking or kyphosis, occurred mainly in the group of whiplash patients (sensitivity 81%, specificity 76%, accuracy 80%).

CONCLUSIONS: Localized kinking greater than 10 degrees and fanning greater than 12 mm are useful measurements by which to separate patients with true whiplash injuries from those with minor ligamentous tears. Flexion and extension views are essential to help define whiplash and other ligamentous injuries of the cervical spine.