Brachioradialis

Brachioradialis

OVERVIEW
Key Points:

• Brachioradialis flexes the elbow with forearm in neutral (`thumbs up position”™).
• Many patients with loss of biceps and brachialis function (through injury to the upper brachial plexus or to the musculocutaneous nerve) will use brachioradialis to flex the elbow.

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EXAMINATION
Muscle Function:
• Primary: Elbow flexion with forearm in neutral.
• Secondary: Assists with supination and pronation, bringing forearm to neutral position.
Palpation: Lateral to the biceps tendon at the elbow.
 
Strength Testing:
Gravity-lessened Test: Position ““ the subject in sitting with 90º of shoulder flexion and internally rotation, 90º elbow flexion, and forearm in neutral with the thumb pointing towards the body. Stabilize ““ the arm or rest on a table at shoulder height. Support – the arm through the normal range of motion.
 
Anti-gravity Test: Position ““ the subject in sitting with shoulder and elbow slightly flexed with forearm in neutral position. Stabilize ““ the anterior shoulder when giving resistance. Resist ““ against elbow flexion while keeping the forearm in neutral/”™thumbs up”™ position (in the direction of elbow extension). Additionally, the subject can place and actively hold elbow flexion at 90º with forearm in neutral position.
 
Possible Substitutions: Biceps brachii and brachialis ““ to avoid this, make sure the elbow is kept in forearm neutral position throughout. Muscles for wrist extensors ““ if this occurs, the forearm would likely turn into pronation. Watching the position of the forearm is important to alleviate these potential substitutions.
 
Relevant Anatomy:
Innervation:
• Roots: C5, C6.
• Nerve: Radial nerve.
• Innervation Route: C5, C6 → radial nerve → brachioradialis branch.
Origin: Proximal â…” of lateral supracondylar ridge of humerus and the lateral intermuscular septum. 
 
Insertion: Lateral side of base of styloid process of radius. 

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Brachioradialis

OVERVIEW
Key Points:

• Brachioradialis flexes the elbow with forearm in neutral (`thumbs up position”™).
• Many patients with loss of biceps and brachialis function (through injury to the upper brachial plexus or to the musculocutaneous nerve) will use brachioradialis to flex the elbow.

FEATURED RESOURCES View All

EXAMINATION
Muscle Function:
• Primary: Elbow flexion with forearm in neutral.
• Secondary: Assists with supination and pronation, bringing forearm to neutral position.
Palpation: Lateral to the biceps tendon at the elbow.
 
Strength Testing:
Gravity-lessened Test: Position ““ the subject in sitting with 90º of shoulder flexion and internally rotation, 90º elbow flexion, and forearm in neutral with the thumb pointing towards the body. Stabilize ““ the arm or rest on a table at shoulder height. Support – the arm through the normal range of motion.
 
Anti-gravity Test: Position ““ the subject in sitting with shoulder and elbow slightly flexed with forearm in neutral position. Stabilize ““ the anterior shoulder when giving resistance. Resist ““ against elbow flexion while keeping the forearm in neutral/”™thumbs up”™ position (in the direction of elbow extension). Additionally, the subject can place and actively hold elbow flexion at 90º with forearm in neutral position.
 
Possible Substitutions: Biceps brachii and brachialis ““ to avoid this, make sure the elbow is kept in forearm neutral position throughout. Muscles for wrist extensors ““ if this occurs, the forearm would likely turn into pronation. Watching the position of the forearm is important to alleviate these potential substitutions.
 
Relevant Anatomy:
Innervation:
• Roots: C5, C6.
• Nerve: Radial nerve.
• Innervation Route: C5, C6 → radial nerve → brachioradialis branch.
Origin: Proximal â…” of lateral supracondylar ridge of humerus and the lateral intermuscular septum. 
 
Insertion: Lateral side of base of styloid process of radius. 

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