What is differences between mioclony and dystonia?

Jerks vs posture: I assume you mean myoclonus. This is a jerk, like a shock, occurring in a limb or head. Dystonia is a fixed posture, often uncomfortable, like a persistent head turn or a curled hand. Myoclonus can be due to seizures or spinal nerve irritation, dystonia is usually a mis-programming of control circuits in the brain, but can be due to certain drugs.

Myoclonus & dystonia: Myoclonus is characterized by a fast jerky movement of a limb or any other part of the body. Dystonia is characterized by a slow continuous movement disorder with a sustained abnormal posture of a limb or body part. Both are involuntary movement disorders with different etiologies and treatments.