Muscle Test: Brachioradialis

Test, Exam and Sign Description

Muscle Testing: Brachioradialis

Origin: Humerus (lateral supracondylar ridge, proximal 2/3)

Lateral intermuscular septum (anterior)

Insertion: Radius (lateral side of shaft just proximal to styloid process)

Innervation: Cervical root(s): C5–6

Nerve: radial nerve

Grading of muscle strength:

Grade	Strength	Description
5*	Normal	Completes range of motion and holds against maximal finger resistance
4*	Good	Completes range against moderate resistance
3	Fair	Completes range of motion with no resistance
2	Poor	Completes range of motion
1	Trace	Palpable or visible contractile activity, which may or may not be accompanied by a flicker of motion
0	Zero	No contractile activity
*The distinction between Grades 4 and 5 is based on comparison with the normal hand and, barring that, extensive experience in testing the hand.

Position of patient's hand and upper extremity

Short sitting with arms at sides. The forearm is in mid-position between pronation and supination.

Examiner’s actions

Stand in front of the patient toward the test side. The hand applying resistance is contoured over the volar (flexor) surface of the forearm proximal to the wrist. The other forearm is placed over the anterior surface of the upper arm and applies counterforce by resisting any upper arm movement.

Instructions for the patient

“Bend your elbow. Hold it. Don’t let me pull it down.”

Presentation Photos and Related Diagrams

BR anatomy illustration. (Hover over right edge to see more images)
This illustration represents the anatomy of the muscle and tendon origin and insertion. Should an individual sustain a laceration as depicted, the observer can assume that the underlying tendon may be at risk for complete transection. A proper examination is needed to determine the integrity of the tendon.

Definition of Positive Result

In muscle testing, a normal result is a positive one. During a normal muscle test, the examiner should observe a normal muscle contraction that can move the joint or tendon against full resistance.

Definition of Negative Result

In muscle testing, an abnormal result is a negative one. During an abnormal muscle test, the examiner should observe an abnormal muscle contraction that can move the joint or tendon. In a complete denervation injury, such as a complete nerve laceration, there will be no evidence of any muscle function and the muscle testing grade will be zero.

Comments and Pearls

The patient’s wrist flexors should remain relaxed throughout the test, as contracting the wrist flexor muscles may assist with elbow flexion.

Diagnoses Associated with Tests, Exams and Signs

CERVICAL RADICULOPATHY

References

1. Hislop JH, Avers D, Brown M. Daniels and Worthingham's Muscle Testing, Techniques of Manual Examination and Performance Testing. 9th ed. St. Louis, Missouri: Elsevier Saunders, 2014, pp. 138–202.