• A disorder in which muscles twitch, causing uncontrollable twisting movements.
  Harvard Dictionary of Health Terms
  Harvard Medical Publishing, 2011
• An abnormally increased muscular tone that causes fixed abnormal postures. There is a slow, intermittent twisting motion that leads to exaggerated turning and posture of the extremities and trunk.
  Human Phenotype Ontology (HPO)
  The Human Phenotype Ontology Project, 2025
• An attitude or posture due to the co-contraction of agonists and antagonist muscles in one region of the body. It most often affects the large axial muscles of the trunk and limb girdles. Conditions which feature persistent or recurrent episodes of dystonia as a primary manifestation of disease are referred to as DYSTONIC DISORDERS. (Adams et al., Principles of Neurology, 6th ed, p77)
  NLM Medical Subject Headings
  U.S. National Library of Medicine, 2025
• Extrapyramidal motor disturbance consisting of slow, sustained contractions of the axial or appendicular musculature; one movement often predominates, leading to relatively sustained postural deviations; acute dystonic reactions (facial grimacing and torticollis) are occasionally seen with the initiation of antipsychotic drug therapy.
  Sadock's Comprehensive Glossary of Psychiatry and Psychology
  BJ Sadock Titles Press, 2012
• Dystonias are sustained involuntary muscle contractions of antagonistic muscle groups in the same body part, leading to sustained abnormal posturing or jerky, twisting, intermittent spasms that can resemble tremors, athetosis, or choreoathetosis. Dystonias can be primary or secondary and can be generalized, focal, or segmental. Diagnosis...
  Merck Manuals
  Merck & Co., Inc., 2025
• Dystonia (from Greek, meaning altered muscle tone) refers to a syndrome of involuntary sustained or spasmodic muscle contractions involving co-contraction of the agonist and the antagonist. The movements are usually slow and sustained, and they often occur in a repetitive and patterned manner; however, they can be unpredictable and...
  Medscape
  WebMD, 2025
• Dystonia is a movement disorder in which your muscles contract involuntarily, causing repetitive or twisting movements.
  Mayo Clinic
  Mayo Foundation for Medical Education and Research, 2025
• Dystonia is a movement disorder characterized by sustained involuntary contractions of agonist and antagonist muscles, often leading to repetitive twisting movements and abnormal postures of the trunk, neck, face, or extremities. It is often associated with unwanted "overflow" contraction of adjacent muscles.
  Epocrates
  Athenahealth, Inc., 2019
• Dystonia, movement disorder characterized by the involuntary and repetitive contraction of muscle groups, resulting in twisting movements, unusual postures, and possible tremor of the involved muscles. As the disorder persists, movement may affect other muscle groups. Although dystonias may occur...
  Encyclopedia Britannica
  Encyclopedia Britannica, Inc., 2025