What does reflex grade 4 indicate?

What does reflex grade 4 indicate?

• A. No contraction.
• B. Diminished response.
• C. Brisk contraction with clonus.
• D. Repetitive rhythmic contractions following strike indicating clonus and upper motor neuron involvement.

Answer: (D)

Grading deep tendon reflexes from 0 to 4 helps describe how reactive the nervous system is. A grade 4 reflex is characterized by a reflex that is not only very brisk but also produces clonus—the reflexive contractions continue in a rhythmic, repetitive way after the strike. This clonus indicates upper motor neuron involvement, meaning there’s increased excitability of the stretch reflex pathway due to CNS (corticospinal tract) dysfunction. In contrast, zero or diminished responses point to reduced activity or lower motor neuron issues, and a simple brisk contraction without clonus would not carry the same implication. So, the description of repetitive rhythmic contractions following the strike directly captures both the brisk, hyperactive nature and the presence of clonus, which signals an upper motor neuron problem.

Grading deep tendon reflexes from 0 to 4 helps describe how reactive the nervous system is. A grade 4 reflex is characterized by a reflex that is not only very brisk but also produces clonus—the reflexive contractions continue in a rhythmic, repetitive way after the strike. This clonus indicates upper motor neuron involvement, meaning there’s increased excitability of the stretch reflex pathway due to CNS (corticospinal tract) dysfunction. In contrast, zero or diminished responses point to reduced activity or lower motor neuron issues, and a simple brisk contraction without clonus would not carry the same implication. So, the description of repetitive rhythmic contractions following the strike directly captures both the brisk, hyperactive nature and the presence of clonus, which signals an upper motor neuron problem.