Dystonia is a persistent attitude or posture in one or other of the extremes of athetoid movement. It may take the form of an over-extension or over-flexion of the hand, torsion of the spine, with arching and twisting of the back or forceful closure of the eyes and a fixed grimace. Dystonia is classified into idiopathic and symptomatic dystonia. Idiopathic dystonia is further divided into generalized, focal and segmental dystonia. Generalized dystonia covers classical torsion dystonia, paradoxical dystonia, myoclonic dystonia, dystonia with diurnal variation and Dopa-responsive dystonia. Dystonic tic, paroxysmal dystonia and hypnotic dystonia show a dystonic posture, although they are also accompanied by various other involuntary movements such as athetosis or chorea. Torticollis, writer's cramp or blepharospasm is assigned to the focal dystonia and Meige syndrome to the segmental dystonia. Symptomatic dystonia is observed in various neurological disorders, including cerebrovascular diseases, Parkinson's disease and Wilson's disease.