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Grading of Muscle Strength (MRC Scale and Its Modifications)

Purpose: To grade a patient's muscle strength.

Description

Major skeletal muscles can be functionally assessed for their strength. Muscles are evaluated individually, with comparison to that of the same muscle on the opposite side of the body. Muscle strength can be monitored over time to follow progression or remission of disease.


The British Medical Research Council (MRC) developed a muscle scale to grade muscle strength from 0 to 5.

 

Muscle Findings

Grade

normal power

5

active movement against gravity and resistance

4

active movement against gravity (but not resistance)

3

active movement with gravity eliminated

2

flicker or trace of muscle contractions

1

no muscle contractions

0

 

where:

• Movement of an extremity against gravity involves lifting it off the bed, while elimination of gravity indicates the limb can be moved to either side while lying on the bed.

 

Because grade 4 covers a relatively broad range of muscle power, this may be subdivided into 2 or more groups to allow for more specific descriptions.

 

Muscle Findings

Grade

normal motor power

5

able to overcome gravity and significant resistance, but strength not quite normal

4++

able to overcome gravity and moderate resistance

4+

able to overcome gravity and mild resistance

4

able to overcome gravity but not resistance

3

unable to overcome the force of gravity, but able to move in the plane of the supported extremity

2

flicker movements only

1

total paralysis

0

 


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Specialty

Objective

ICD-10