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.

Contents 1 Action 2 Innervation 3 Additional images 4 External links

[edit] 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.

With the insertion of the muscle so far from the fulcrum of the elbow, the brachioradialis does not generate as much force as the brachialis or the biceps. It is effective mainly when those muscles have already partially flexed at the elbow. The brachioradialis flexes the forearm at the elbow, especially when quick movement is required and when a weight is lifted during slow flexion of the forearm.

The muscle is used to stabilize the elbow during rapid flexion and extension while in a midposition, such as in hammering. The brachioradialis is synergistic with the brachialis and biceps brachii; the triceps brachii and anconeus are antagonistic.

[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] 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.

[edit] 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)

v • d • e List of muscles of upper limbs (TA A04.6, GA 4.432) Shoulder deltoid · rotator cuff (supraspinatus, infraspinatus, teres minor, subscapularis) · teres major fascia: Deltoid fascia · Supraspinous fascia · Infraspinous fascia Arm (compartments) Anterior coracobrachialis · biceps brachii · brachialis Posterior triceps brachii · anconeus · Articularis cubiti Fascia Axillary sheath · Axillary fascia · Brachial fascia · intermuscular septa (Lateral, Medial) Other spaces (Quadrangular space, Triangular space, Triangular interval) Forearm Anterior superficial: pronator teres · palmaris longus · flexor carpi radialis · flexor carpi ulnaris · flexor digitorum superficialis deep: pronator quadratus · flexor digitorum profundus · flexor pollicis longus Posterior superficial: mobile wad (brachioradialis, extensor carpi radialis longus and brevis) · extensor digitorum · extensor digiti minimi · extensor carpi ulnaris deep: supinator · anatomical snuff box (abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus) · extensor indicis Fascia Bicipital aponeurosis · common tendons (Extensor, Flexor) · Antebrachial fascia Other Cubital tunnel Hand Lateral volar thenar (opponens pollicis, flexor pollicis brevis, abductor pollicis brevis) · adductor pollicis Medial volar hypothenar (opponens digiti minimi, flexor digiti minimi brevis, abductor minimi digiti) · palmaris brevis Intermediate lumbrical · interossei (dorsal, palmar) Fascia posterior: Extensor retinaculum · Extensor expansion anterior: Flexor retinaculum · Palmar aponeurosis

Bowden, Bradley S. Bowden, Joan M. An Illustrated Atlas of Skeletal Muscles. 2nd ed. © 2002

Saladin, Kenneth S. Anatomy & Physiology. 4th ed. © 2007