Brachioradialis

Brachioradialis is a muscle

Muscle

Muscle is the contractile tissue of the body and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...

 of the forearm

Forearm

The forearm is the structure and distal region of the upper limb, between the elbow and the wrist.. The term forearm is used in anatomy to distinguish it from the arm which is often misused to describe the entire appendage of the upper limb and technically means only the region of the upper arm...

 that acts to flex the forearm at the elbow

Elbow

The elbow is the region surrounding the elbow-joint—the ginglymus or hinge joint in the middle of the arm. Three bones form the elbow joint: the humerus of the upper arm, and the paired radius and ulna of the forearm....

. It is also capable of both pronation

Pronation

In anatomy, pronation is a rotational movement of the forearm at the radioulnar joint, or of the foot at the subtalar and talocalcaneonavicular joints. For the forearm, when standing in the anatomical position, pronation will move the palm of the hand from an anterior-facing position to a...

 and supination

Supination

Supination is a position of either the forearm or foot; in the forearm when the palm faces anteriorly, or faces up . Supination in the foot occurs when a person appears "bow-legged" with their weight supported primarily on the anterior of their feetThe hand is supine in the anatomical position...

, 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

Radius (bone)

The radius is the bone of the forearm that extends from the lateral side of the elbow to the thumb side of the wrist. The radius is situated on the lateral side of the ulna, which exceeds it in length and size. It is a long bone, prism-shaped and slightly curved longitudinally...

 by way of the brachioradialis tendon, and to the lateral supracondylar ridge

Lateral supracondylar ridge

The lower part of the lateral border of the body of the humerus forms a prominent, rough margin, a little curved from behind forward, the lateral supracondylar ridge , which presents an anterior lip for the origin of the Brachioradialis above, and Extensor carpi radialis longus below, a posterior...

 of the humerus

Humerus

The humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....

.

Brachioradialis flexes the forearm at the elbow.

Brachioradialis is a muscle

Muscle

Muscle is the contractile tissue of the body and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...

 of the forearm

Forearm

The forearm is the structure and distal region of the upper limb, between the elbow and the wrist.. The term forearm is used in anatomy to distinguish it from the arm which is often misused to describe the entire appendage of the upper limb and technically means only the region of the upper arm...

 that acts to flex the forearm at the elbow

Elbow

The elbow is the region surrounding the elbow-joint—the ginglymus or hinge joint in the middle of the arm. Three bones form the elbow joint: the humerus of the upper arm, and the paired radius and ulna of the forearm....

. It is also capable of both pronation

Pronation

In anatomy, pronation is a rotational movement of the forearm at the radioulnar joint, or of the foot at the subtalar and talocalcaneonavicular joints. For the forearm, when standing in the anatomical position, pronation will move the palm of the hand from an anterior-facing position to a...

 and supination

Supination

Supination is a position of either the forearm or foot; in the forearm when the palm faces anteriorly, or faces up . Supination in the foot occurs when a person appears "bow-legged" with their weight supported primarily on the anterior of their feetThe hand is supine in the anatomical position...

, 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

Radius (bone)

The radius is the bone of the forearm that extends from the lateral side of the elbow to the thumb side of the wrist. The radius is situated on the lateral side of the ulna, which exceeds it in length and size. It is a long bone, prism-shaped and slightly curved longitudinally...

 by way of the brachioradialis tendon, and to the lateral supracondylar ridge

Lateral supracondylar ridge

The lower part of the lateral border of the body of the humerus forms a prominent, rough margin, a little curved from behind forward, the lateral supracondylar ridge , which presents an anterior lip for the origin of the Brachioradialis above, and Extensor carpi radialis longus below, a posterior...

 of the humerus

Humerus

The humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....

.

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

Biceps brachii muscle

In human anatomy, the biceps brachii is a muscle located on the upper arm. The biceps has several functions, the most important being to rotate the forearm and to flex the elbow.-Terminology:...

 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

Radial nerve

The radial nerve is a nerve in the human body that supplies the upper limb. It supplies the triceps brachii muscle of the arm, as well as all 12 muscles in the posterior osteofascial compartment of the forearm, as well as the associated joints and overlying skin.It originates from the posterior...

. 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

Triceps brachii muscle

The triceps brachii muscle is the large muscle on the back of the human upper limb. It is the muscle principally responsible for extension of the elbow joint...

, anconeus

Anconeus muscle

The anconeus muscle is a small muscle on the posterior aspect of the elbow joint.Some consider anconeus to be a continuation of the triceps brachii muscle...

, and extensor carpi radialis longus. (All other posterior compartment muscles that receive radial innervation are supplied by the deep branch of the radial nerve

Deep branch of the radial nerve

The deep branch of the radial nerve winds to the back of the forearm around the lateral side of the radius between the two planes of fibers of the Supinator, and is prolonged downward between the superficial and deep layers of muscles, to the middle of the forearm.Considerably diminished in size,...

.)

External links

- "Transverse section through the left arm just proximal to the elbow." - "Superficial muscles of the anterior (flexor) compartment of the left forearm." - "Superficial muscles of the posterior (extensor) compartment of the left forearm."