Brachioradialis Muscle

Origin

The brachioradialis muscle originates from the:

- superior two thirds of the lateral supracondylar ridge of the humerus, which is located superior to the origin site of the extensor carpi radialis longus muscle;

- adjacent intermuscular septa of the arm.

Insertion

The fibers of the brachioradialis muscle travel inferiorly and insert, via a flat tendon, onto the lateral aspect of the distal part of radius, which is located superior to the radial styloid process.

Key Features & Anatomical Relations

The brachioradialis muscle is one of the muscles of the superficial part of the posterior compartment of the forearm. It is a long fusiform type of skeletal muscle. In the middle of the forearm, the muscle belly gives rise to a flat tendon, which travels inferiorly along the lateral aspect of the forearm to its insertion site.

The brachioradialis muscle is located:

- Anterior to the extensor carpi radialis longus muscle;

- Lateral to the pronator teres and flexor carpi radialis muscles;

- Superficial to the radial artery, and the radial nerve;

- Deep to the tendons of the abductor pollicis longus and extensor pollicis brevis (at its tendon).

The medial margin of the brachioradialis muscle defines the lateral boundary of the cubital fossa.

Actions & Testing

The brachioradialis muscle flexes the forearm at the elbow joint, contracting most powerfully when the forearm is in the mid-pronated position. It can be tested by flexing the forearm at the elbow joint against resistance while the forearm is held in the mid-pronated position, during which it can be seen and palpated (Standring, 2016).

References

Standring, S. (2016) Gray's Anatomy: The Anatomical Basis of Clinical Practice. Gray's Anatomy Series 41st edn.: Elsevier Limited.