Difference between revisions of "Clonus"

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Moccia M, Spina E, Allocca R, Barone P, Vitale C. Teaching Video NeuroImages: Finger clonus: When the pupil surpassed his master. Neurology 2016 ;86:e118-9.
 
Moccia M, Spina E, Allocca R, Barone P, Vitale C. Teaching Video NeuroImages: Finger clonus: When the pupil surpassed his master. Neurology 2016 ;86:e118-9.
  
[[Category: Motor signs]]
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[[Category: Motor Signs]]

Revision as of 21:18, 21 November 2016

The video demonstrates sustained ankle clonus in a patient with a spastic hemiparesis after a stroke. Clonus is a series of rhythmic involuntary muscular contractions induced by the sudden passive stretching of a muscle or tendon. It often accompanies the spasticity and hyperactive DTRs seen in corticospinal tract disease. Clonus occurs most frequently at the ankle, knee, elbow and wrist, occasionally elsewhere. The response is a series of alternating contractions of the agonist and antagonist. Ankle clonus consists of a series of rhythmic alternating flexions and extensions of the ankle. Unsustained clonus fades away after a few beats, sustained clonus may persist as long as the examiner continues to hold slight pressure against the sold of the foot. Unsustained (transient, exhaustible), symmetric ankle clonus may occur in normal individuals with physiologically fast DTRs. Sustained clonus is never normal.

Ankle clonus is easiest to obtain if the examiner grasps the foot from below and quickly pushes upward while maintaining slight pressure on the sole at the end of the movement. Patellar clonus consists of a series of rhythmic up-and-down movements of the patella elicited by a quick, downward thrust. Clonus of the wrist (see Biotti and Vighetto), or of the fingers (see Moccia et al ) may be produced by a sudden passive extension of the wrist or fingers. A quick supination movement of the forearm can induce pronator clonus. Clonus of the jaw occurs occasionally (see Iodice at el).

References

Biotti D, Vighetto A. Images in clinical medicine. Upper limb clonus. N Engl J Med 2013;369:e12.

Campbell WW. DeJong's the neurologic examination, 7th ed. Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins, 2013.

Fareedy SB, Pathak R. Ankle clonus. Clin Case Rep. 2015;3:520.

Iodice R, Manganelli F, Dubbioso R, et al. Teaching video neuroimages: clonus of the lower jaw: an old sign that comes back. Neurology 2014;82:e96.

Moccia M, Spina E, Allocca R, Barone P, Vitale C. Teaching Video NeuroImages: Finger clonus: When the pupil surpassed his master. Neurology 2016 ;86:e118-9.