Brachioradialis

Brachioradial muscle
Anterior view of muscles of the left 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
Actions	Flexion of forearm

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; for this reason it is also called "the beer drinker muscle." It is attached to the distal styloid process of the radius by way of the brachioradialis tendon, and to the lateral supracondylar ridge of the humerus.

Action

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.

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.)

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 radial artery.	The radial and ulnar arteries.
Ulnar and radial arteries. Deep view.	Nerves of the left upper extremity.

External links

• LUC brds
• UWASH brachioradialis
• SUNY Figs 07:01-09 - "Transverse section through the left arm just proximal to the elbow."
• SUNY Figs 07:03-07 - "Superficial muscles of the anterior (flexor) compartment of the left forearm."
• SUNY Figs 09:02-02 - "Superficial muscles of the posterior (extensor) compartment of the left forearm."
• lesson5musofpostforearm at The Anatomy Lesson by Wesley Norman (Georgetown University)