Brachioradialis

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Brachioradial muscle
Muscles of the forearm with Brachioradialis shown in blue.
Cross-section through the middle of the forearm. (Brachioradialis labeled at center left, sixth from the top.)
Latin musculus brachioradialis
Gray's subject #125 451
Origin: Lateral supracondylar ridge of the humerus
Insertion: Distal radius (Radial styloid process)
Artery: radial recurrent artery
Nerve: radial nerve
Action: Flexion of forearm
Dorlands/Elsevier m_22/12548506

Brachioradialis is a muscle of the forearm that acts to flex the forearm at the elbow. It is also capable of both pronation and supination, depending on the position of the forearm. It is attached to the distal styloid process of the radius and the lateral supracondylar ridge of the humerus.

Contents

[edit] Action

The brachioradialis flexes the forearm at the elbow. When the forearm is pronated, the brachioradialis tends to supinate as it flexes. In a supinated position, it tends to pronate as it flexes.

The brachioradialis is a stronger elbow flexor when the forearm is in a midposition between supination and pronation at the radioulnar joint. When pronated, the brachioradialis is more active during elbow flexion since the biceps brachii is in a mechanical disadvantage.

[edit] Innervation

Despite the bulk of the muscle body being visible from the anterior aspect of the forearm, the brachioradialis is a posterior compartment muscle and consequently is innervated by the radial nerve. Of the muscles that receive innervation from the radial nerve, it is one of only four that receive input directly from the radial nerve. The other three are the triceps, anconeus, and extensor carpi radialis longus. (All other posterior compartment muscles that receive radial innervation are supplied by the deep branch of the radial nerve.)

[edit] Appearance

If a person half-pronates their arm, to make a fist as if holding a handled vessel of beer, then puts their fist under a table or desk and tries to flex at the elbow, the brachioradialis will stand out of the forearm, visible under the skin.

[edit] Additional images

Left humerus. Anterior view.

Bones of left forearm. Anterior aspect.

Front of the left forearm. Superficial muscles.

Posterior surface of the forearm. Superficial muscles.

The brachial artery.

The radial and ulnar arteries.

Ulnar and radial arteries. Deep view.

Nerves of the left upper extremity.

[edit] External links


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