MRI Findings of Injury to the Longus Colli Muscle in Patients With Neck Trauma

The longus colli muscle (LCM) forms the bulk of the deep flexor muscles of the neck. To our knowledge, very little information on the effects of trauma on this muscle group has been published. We describe MRI findings related to injury of the LCM in patients with a history of neck trauma. A radiology department database was searched to identify patient medical records from 2008 to 2013 that included the keywords "longus colli" and "deep flexors." Patients with fractures and ligament injuries were excluded. Patients with other obvious large soft-tissue injuries and nontraumatic conditions were also omitted. A total of 12 patients met the inclusion criterion of having an isolated or predominant injury to the LCM. Five patients had been involved in a motor vehicle accident, and seven patients had fallen. Eleven patients had undergone a CT examination before MRI was performed. No fractures were noted on CT. MRI examinations of the cervical spine were obtained for the following reasons: for increased prevertebral soft-tissue swelling noted on a CT scan plus neck pain (n = 6), for neck pain only (n = 4), or as part of a routine protocol for assessment of obtunded patients (n = 2). Eight of the 12 patients had isolated injury to the LCM. The remaining four patients also had minor injuries to the other neck muscles. The MR image showed swelling and T2 hyperintensity in the LCM and revealed free fluid in the prevertebral space. Isolated injury to the LCM may occur in neck injuries. The MRI findings indicating such injury include increased T2 signal, swelling of the muscle, and the presence of prevertebral fluid.