A form of movement marked by contractions and relaxations of a muscle, occurring in rapid succession seen with, among other conditions, spasticity and some seizure disorders. SEE ALSO: contraction. [G. klonos, a tumult]
- ankle c. a rhythmic contraction of the calf muscles following a sudden passive dorsiflexion of the foot, the leg being semiflexed.
- toe c. alternating movements of flexion and extension of the great toe following forcible extension at the metatarsophalangeal joint.
- wrist c. rhythmical contractions and relaxations of the muscles of the forearm excited by a forcible passive extension of the hand.

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clo·nus 'klō-nəs n a series of alternating contractions and partial relaxations of a muscle that in some nervous diseases occurs in the form of convulsive spasms involving complex groups of muscles and is believed to result from alteration of the normal pattern of motor neuron discharge compare TONUS (2)

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rhythmical contraction of a muscle in response to a suddenly applied and then sustained stretch stimulus. It is most readily obtained at the ankle when the examiner bends the foot sharply upwards and then maintains an upward pressure on the sole. It is caused by an exaggeration of the stretch reflexes and is usually a sign of disease in the brain or spinal cord.

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clo·nus (kloґnəs) [Gr. klonos turmoil] 1. alternate muscular contraction and relaxation in rapid succession. 2. a continuous rhythmic reflex tremor initiated by the spinal cord below an area of spinal cord injury, set in motion by reflex testing. clonic adj

Medical dictionary. 2011.

Look at other dictionaries:

  • Clonus — (del latin clonus y este del Griego klonós, que refiere a movimiento violento, confuso) es un término médico usado para describir uno de los signos de ciertas alteraciones neurológica que consiste en la aparición involuntaria de contracciones… …   Wikipedia Español

  • Clonus — (from the Greek for violent, confused motion ) is a series of involuntary muscular contractions and relaxations. Clonus is a sign of certain neurological conditions, and is particularly associated with upper motor neuron lesions such as in stroke …   Wikipedia

  • clonus — [ klɔnys ] n. m. • 1862; du gr. klonos « agitation » ♦ Méd. Contraction rythmique déclenchée par la traction brusque de certains muscles, traduisant une exagération des réflexes. Clonus de la rotule, du pied, de la main. ● clonus nom masculin… …   Encyclopédie Universelle

  • clonus — clónus s. n. Trimis de siveco, 10.08.2004. Sursa: Dicţionar ortografic  CLÓNUS s.n. (med.) Serie de convulsii (1), denotând existenţa unei leziuni a centrilor nervoşi motori superiori; clonie. [< fr. clonus, cf. gr. klonos – agitaţie]. Trimis …   Dicționar Român

  • clonus — m. neurol. Serie de contracciones rítmicas e involuntarias de un músculo estriado o conjunto de ellos provocada por la extensión pasiva y brusca de sus tendones; es un consecuencia de una lesión de la vía piramidal, pero también se observa en el… …   Diccionario médico

  • Clonus — Clo nus, n. [NL., fr. Gr. klo nos violent, confused motion.] (Med.) A series of muscular contractions due to sudden stretching of the muscle, a sign of certain neuropathies. [Webster 1913 Suppl.] …   The Collaborative International Dictionary of English

  • Clonus — vgl. Klonus …   Das Wörterbuch medizinischer Fachausdrücke

  • clonus — (n.) violent muscular spasms, 1817, from Modern Latin, from Gk. klonos turmoil, violent motion, confusion, tumult, from PIE *kel to drive, set in motion …   Etymology dictionary

  • clonus — [klō′nəs] n. [ModL < Gr klonos, turmoil < kelomai, to start, impel < IE base * kel > HOLD1, < L celer, swift] a series of muscle spasms induced by sudden stretching or certain nervous diseases: see TONUS …   English World dictionary

  • Clonus — 1Clo|nus der; , se <über nlat. clonus aus gr. klo̅n »Schössling, Zweig«> svw. ↑Klon. Clonus 2 2Clo|nus der; , se <zu 1↑Clonus> ohne natürliche Zeugung aus lebenden Zellen entwickelter künstlicher Mensch …   Das große Fremdwörterbuch

  • Clonus — Un clonus est une série de contractions rapides et réflexes apparaissant suite à l’étirement brusque de certains muscles. Le clonus est le témoin d’une lésion du faisceau pyramidal. Portail de la médecine Catégorie : Signe cli …   Wikipédia en Français

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