<unk>  or focal hand dystonia (FHD) is an idiopathic movement disorder of adult onset, characterized by abnormal posturing and movement of the hand and/or forearm during tasks requiring skilled hand use, such as writing. Overcontraction of affected muscles, cocontraction of agonist and antagonist pairs, and activation of muscles inappropriate to a task all impair use of the affected hand.<unk>  is a task-specific focal dystonia of the hand. 'Focal' refers to the symptoms being limited to one location (the hand in this case), and 'task-specific' means that symptoms first occur only when the individual engages in a particular activity.<unk>  first affects an individual by interfering with their ability to<unk>  especially for prolonged periods of time. Epidemiologic studies report a prevalence of 7–69 per million population for<unk> , which explains its recognition as a rare disease, like all other forms of dystonia.
Writer's cramp
Digitalis
Sympathicolysis
Abdominal angina
Exercise-associated muscle cramps
Acathexis
Renal angina
Rectal pain