MRC (Medical Research Council) Strength Scale
The Medical Research Council (MRC) scale is the clinical reference system to manually evaluate and grade muscle strength in patients with suspected neuromuscular pathology or motor weakness. It is graded from 0 to 5 as follows:
- Grade 0: There is no visible or palpable muscle contraction.
- Grade 1: A slight muscle contraction (indication or trace) is detected, but there is no joint movement.
- Grade 2: Active movement that cannot overcome gravity (only moves if gravity is removed).
- Grade 3: Complete active movement that overcomes gravity, but does not resist any external force.
- Grade 4: Active movement that overcomes gravity and offers some resistance to the examiner (moderate weakness).
- Grade 5: Normal muscular strength, overcomes gravity and maximum expected resistance.