MRC Scale for Muscle Strength

What is the MRC Scale for Muscle Strength?

The Medical Research Council (MRC) Scale for Muscle Strength is a widely recognized tool to asssess muscle strength and evaluate weakness in patients, particularly those with suspected neurologic diseases. The MRC scale systematically assesses muscles and the peripheral nervous system, including important spinal nerve roots and peripheral nerve injuries, ensuring a comprehensive evaluation.

The MRC scale assesses key muscle groups in both the upper and lower extremities. It helps differentiate true weakness from poor endurance, providing accurate insights into the patient's muscle power and overall strength.

This scale provides standardized muscle strength grading in the upper and lower extremities for a quantifiable measure essential for diagnosing suspected neurologic disease and monitoring neuromuscular conditions. It also demonstrates reasonable interrater reliability, making it a trusted method for evaluating muscle strength by different practitioners.

How do healthcare professionals use this scale?

Simply put, the scale is used to evaluate each muscle group while applying resistance. The scale uses a 0 to 5 grading system to evaluate the strength of specific muscle groups. Each muscle group is tested individually, and the strength is graded according to the following scale:

• Grade 0: No muscle activation.
• Grade 1: Trace muscle activation, such as a twitch, without achieving full range of motion.
• Grade 2: Muscle activation with gravity eliminated, achieving full range of motion.
• Grade 3: Muscle activation against gravity, full range of motion.
• Grade 4: Muscle activation against some resistance, full range of motion.
• Grade 5: Muscle activation against the examiner’s full resistance and range of motion.

How are the scores used?

After each muscle group is graded, the scores for all the limbs are summed up. The total score can range from 0 to 60 (15 per limb), with 60 indicating normal muscle strength across all limbs and 0 indicating no muscle activation (quadriplegia).

Next steps after using this scale

After performing MRC scale for muscle strength, take several steps to ensure the results are effectively used for patient care.

• Communicate results: Record MRC scores clearly in the patient's medical record, noting any asymmetries or weaknesses. Share results with the team using standardized formats for consistency.
• Develop a treatment plan: Design a rehabilitation program targeting weak muscles identified by the MRC scale. Incorporate exercises and therapies to improve overall function and quality of life. Collaborate with specialists for a comprehensive treatment plan, ensuring medical, physical, and psychological care coordination.
• Patient education and support: Explain the MRC scale results and their implications to the patient. Emphasize the importance of muscle strength for overall health and daily functioning, providing access to educational materials, support groups, and community programs if needed. Set realistic goals for improving strength and function. Encourage active participation and adherence to prescribed exercises and therapies.
• Monitoring and reassessment: Schedule regular follow-ups to monitor progress and reassess muscle strength. Adjust the treatment plan as needed. Develop a long-term management plan with periodic assessments and ongoing support.

How to use our MRC Scale for Muscle Strength template

The MRC Scale for Muscle Strength is used for grading, so you actually only use it in the middle of doing a muscle strength exam. However, our template contains fields for recording information. Here's how that process would go:

1. Ensure you have downloaded the scale template from the app or the website, as well as a pen or digital device for recording scores.
2. Inform the patient about the steps involved in the muscle strength testing. Address any concerns or questions the patient may have to alleviate anxiety. Make sure the patient is comfortable and understands the purpose of the assessment.
3. Position the patient appropriately for each muscle group to be tested. Ensure the patient is stable and comfortable to prevent movement from interfering with the assessment.
4. Test each muscle group. Here are some of the general guidelines you can follow for each muscle group.
   • Shoulder abductors: Test both the left and right shoulder abductors. Apply resistance as the patient attempts to abduct (lift) their arms sideways.
   • Elbow flexors: Test both the left and right elbow flexors. Apply resistance as the patient attempts to flex (bend) their elbows.
   • Wrist extensors: Test both the left and right wrist extensors. Apply resistance as the patient attempts to extend (straighten) their wrists.
   • Hip flexors: Test both the left and right hip flexors. Apply resistance as the patient attempts to flex (lift) their thighs towards their abdomen.
   • Knee extensors: Test both the left and right knee extensors. Apply resistance as the patient attempts to extend (straighten) their knees.
   • Foot dorsiflexors: Test both the left and right foot dorsiflexors. Apply resistance as the patient attempts to dorsiflex (lift) their feet upwards.
5. Use the MRC Scale for grading, which is indicated in the template. You can also document each muscle group's score in the template's appropriate section. Ensure scores are recorded for both the left and right sides.
6. Add the scores for all muscle groups to calculate the total score. The total score can range from 0 (quadriplegic) to 60 (normal).