Clonus
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.