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Description[edit | edit source]
The brachioradialis muscle is the most superficial muscle on the radial side of the forearm. It forms the lateral side of the cubital fossa. It's often fused proximally with the brachialis. It has a thin belly that descends in the mid forearm, where its long flat tendon begins, then the tendon continues to the radius. It is also known as supinator longus.
Origin[edit | edit source]
Lateral supracondylar rigid of the humerus and lateral intermuscular septum.
Insertion[edit | edit source]
Styloid process of the radius.
Nerve[edit | edit source]
Due to its location in the posterior compartment of the forearm the brachioradialis is innervated by the radial nerve. The innervation involves contribution from C5-C6 spinal nerve roots (C7 innervation sometimes is cited).
Artery[edit | edit source]
Radial recurrent artery from the radial artery.
Function[edit | edit source]
The brachioradialis flexes the forearm at the elbow. Depending on the position of the hand during the flexion, the brachioradialis can tend to move the hand to neutral.
A EMG study by Michael R. Boland, found that while neutral forearm position is thought to result in the strongest brachioradialis activation, that the greatest EMG activity from the brachioradialis occurs during elbow flexion tasks regardless of forearm position. The study also found that during rotational tasks, higher EMG activity was recorded during pronation as compared to supination tasks, indicating that the brachioradialis muslce appear to function as a pronator than a supinator.
A study by Tim Kleiber et al, found increased activity of the brachioradialis mucle in elbow flexion from forearm pronation position. The increased activity of the brachioradialis in forearm pronation compensates for the mechanically disadvantaged biceps brachii muscle in foreram pronation as its tendon is wrapped around the radial tuberosity.
Clinical relevance[edit | edit source]
Wartenberg syndrome, is a type of radial nerve neuropathy that occurs when the superficial radial nerve is compressed by the brachioradialis and extensor carpi radialis longus tendon. The compression on the radial nerve increases with forearm pronation. It results in sensory manifestations only of burning pain and paresthesia over the dorsum of the wrist, hand and dorsal surface of the thumb, index and middle fingers.
The brachioradialis tendon is used clinically to test C6 spinal nerve root. Which is affected in C5-C6 disc herniation.
In midshaft fracture of the humerous, the brachioradialis and extensor carpi radialis longus are the first two muscle to recover innervation following the injury of the radial nerve in the radial groove, making them important to check for radial nerve recovery.
Assessment[edit | edit source]
Palpation[edit | edit source]
Palpation will be on the anterolateral surface of the forearm.
Muscle Test[edit | edit source]
The MMT is usually done for the three main elbow flexors (biceps, brachialis and brachioradialis) by asking the patient to bend his/her elbow against resistance and start grading, but in try to focus on the brachioradialis, we will ask the patient to bend the the forearm with some degree of pronation (midposition).
Note: the wrist flexor muscles should remain relaxed throughout the test, because strongly contracting wrist flexors may assist in elbow flexion. 
Treatment[edit | edit source]
Strengthening Exercise[edit | edit source]
In supine, sitting or standing position and by having the forearm in midposition, slowly start bending with any suitable type and degree of resistance given by the therapist, such as dumbbells, sand packs or theraband.
Stretching Exercise[edit | edit source]
To stretch the brachioradialis muscle extend the elbow, interlace your fingers of both hands and using the other hand flex the wrist of the affected arm and inwardly rotate the arm so your hand is facing outwards.
References[edit | edit source]
- ↑ Gray, Henry. Anatomy of the Human Body. Philadelphia: Lea & Febiger, 1918; Bartleby.com, 2000. www.bartleby.com/107/125.html
- ↑ 2.0 2.1 2.2 2.3 2.4 Helen J.Hislop Jacqueline Montgomery,Muscle Testing,2007,8th edition.
- ↑ Brachioradialis Anatomy: Origin, Insertion, Action [Internet]. The Wellness Digest. 2014 [cited 2018 Jul 4]. Available from: https://thewellnessdigest.com/brachioradialis-anatomy/
- ↑ Marieb EN, Hoehn K. Human anatomy & physiology. 10th ed. Boston, Ma: Pearson; 2016.
- ↑ Boland MR, Spigelman T, Uhl TL. The function of brachioradialis. J Hand Surg Am. 2008 Dec;33(10):1853–9.
- ↑ Kleiber T, Kunz L, Disselhorst-Klug C. Muscular coordination of biceps brachii and brachioradialis in elbow flexion with respect to hand position. Frontiers in physiology. 2015 Aug 6;6:215.
- ↑ 7.0 7.1 7.2 7.3 Lung BE, Bisogno M. Anatomy, Shoulder and Upper Limb, Forearm Brachioradialis Muscle.
- ↑ 8.0 8.1 TheFightChiro. Brachioradialis stretch. Available from: https://www.youtube.com/watch?time_continue=40&v=xJcuhXa13N8&feature=emb_logo [last accessed 20/2/2021]