MRC Muscle Power Scale – Grade 3 — SCE Neurology MCQ

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EasyMultiple Sclerosis & CNS InflammationMRC Muscle Power Scale – Grade 3SCE Neurology

A 45-year-old man with known MS develops new lower limb weakness. His neurologist performs a clinical examination and finds UMN signs. She uses the MRC scale to grade muscle power. What does MRC grade 3 indicate?

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Correct answer: D — Active movement against gravity

The MRC (Medical Research Council) muscle power scale: Grade 0 = no contraction; Grade 1 = flicker/trace of contraction; Grade 2 = active movement with gravity eliminated (horizontal plane only); Grade 3 = active movement against gravity (can lift the limb); Grade 4 = active movement against gravity and resistance (subdivided into 4−, 4, 4+); Grade 5 = normal power. MRC 3 is a functionally important threshold — it indicates the patient can actively move the limb against gravity but not against additional resistance. A: Grade 0. B: Grade 1. D: Grade 4. E: Grade 5.

Reference: Medical Research Council Muscle Power Scale