The development of focal hand dystonia after a traumatic injury of the central or the peripheral nervous system is a rare condition with multifactorial predisposing factors. We report on a patient who developed focal dystonia of the left hand after a cervical whiplash injury. Magnetic resonance imaging did not show cerebral or spinal lesions, whereas a brain F-FDG PET scan revealed hypometabolism of the right primary sensory-motor cortex extending to the inferior and superior parietal lobule. The patient had a history of recurrent migraine attacks. Four months before the whiplash injury, she had transient dystonic posture of the left hand during a hemiplegic migraine attack. Brain magnetic resonance imaging scan and neurovascular investigations were negative. Among the predisposing factors to the development of trauma-induced dystonia, a putative role of neuronal hyperexcitability, shared by migraine and dystonia, is discussed.