Whiplash following a motor vehicle accident can result in chronic neck and arm pain. Patients frequently present with cutaneous hypersensitivities and hypoesthesia, but without obvious clinical signs of nerve injury. T2-weighted magnetic resonance imaging (MRI) has previously been used to identify nerve pathology.• OBJECTIVES:
To determine whether there are signs of peripheral nerve pathology on MRI in patients with chronic arm and neck pain following whiplash injury.• METHODS:
This cross-sectional study used T2-weighted MRI to examine the brachial plexus and median nerve in patients and age-matched, healthy control subjects. Clinical examination included tests of plexus and nerve trunk mechanical sensitivity.• RESULTS:
The T2 signal intensity was greater in the brachial plexus and median nerve at the wrist in the patient group (mean intensity ratio = 0.52 ± 0.13 and 2.09 ± 0.33, respectively) compared to the control group (mean intensity ratio = 0.45 ± 0.07 and 1.38 ± 0.31, respectively; P<.05). Changes in median nerve morphology were also observed, which included an enlargement (mean area: patient group, 8.05 ± 1.29 mm2; control group, 6.52 ± 1.08 mm2; P<.05) and flattening (mean aspect ratio: patient group, 2.46 ± 0.53; control group, 1.62 ± 0.30; P<.05) at the proximal carpal row. All patients demonstrated signs of nerve trunk mechanical sensitivity.• CONCLUSION:
These findings suggest that patients with chronic whiplash may have inflammatory changes and/or mild neuropathy, which may contribute to symptoms.