Which statement describes a positive clonus finding?

Which statement describes a positive clonus finding?

• A. Rhythmic jerking beats of the foot with dorsiflexion released
• B. A single twitch of the foot
• C. No movement of the foot
• D. Continuous spasm of the leg

Answer: (A)

Clonus is a repeated, rhythmic contraction of a muscle in response to a sudden stretch, indicating upper motor neuron involvement and hyperreflexia. To test it, rapidly dorsiflex the ankle and hold the position; if positive clonus is present, you’ll see rhythmic, beating jerks of the foot that continue for several cycles while the stretch is maintained. This rhythmic beating distinguishes clonus from a single twitch, no movement, or a continuous only-spasm pattern. So the description of rhythmic jerking beats of the foot during the stretch is the best representation of a positive clonus finding.

Clonus is a repeated, rhythmic contraction of a muscle in response to a sudden stretch, indicating upper motor neuron involvement and hyperreflexia. To test it, rapidly dorsiflex the ankle and hold the position; if positive clonus is present, you’ll see rhythmic, beating jerks of the foot that continue for several cycles while the stretch is maintained. This rhythmic beating distinguishes clonus from a single twitch, no movement, or a continuous only-spasm pattern. So the description of rhythmic jerking beats of the foot during the stretch is the best representation of a positive clonus finding.