Lesions in the basal ganglia, brainstem, cerebellum, or cortical areas (parietal and frontal) may result in dystonia¹.  Most lesions responsible for symptomatic dystonia involve the basal ganglia or thalamus. Delayed onset of dystonia is common, following an acute focal lesion or a traumatic brain injury².

 
There may be a relationship between the localization of the lesion and the body region affected by dystonia:

1. Thalamic lesions are more likely to result in hand dystonia.
2. Brainstem lesions may result in cranial dystonias such as blepharospasm
3. Putaminal lesions have been associated with hemidystonia or limb dystonia.

Dystonia has been correlated with lesions of the contralateral lentiform nucleus, putamen, external globus pallidus, posterior and posterior lateral thalamus, red nucleus, or subthalamic nucleus, or a combination of these structures.
 

Basal Ganglia
The lentiform nucleus (putamen and globus pallidus) are the most frequent sites affected in those with dystonia. However, the caudate nucleus may also be implicated.

Thalamus
The posterior/posterolateral and midline thalamic nuclei (paramedian thalamus), and the subthalamic region are the most common sites. Thalamic lesions may result in hemidystonia, focal dystonia of the hand or arm, and segmental dystonia of the upper body.

Cerebellum
Blepharospasm has been noted with bilateral lesions of the cerebellar hemispheres, and torticollis may occur with lesions (hemangioblastoma and cavernous angioma) of the cerebellar hemispheres³.