In human anatomy, extensor carpi radialis brevis is a muscle in the forearm that acts to extend and abduct the wrist. It is shorter and thicker than its namesake extensor carpi radialis longus which can be found above the proximal end of the extensor carpi radialis brevis.

Origin and insertion

It arises from the

lateral epicondyle of the humerus The lateral epicondyle of the humerus is a large, tuberculated eminence, curved a little forward, and giving attachment to the radial collateral ligament of the elbow joint, and to a tendon common to the origin of the supinator and some of the ...

, by the

common extensor tendon The common extensor tendon is a tendon that attaches to the lateral epicondyle of the humerus. Structure The common extensor tendon serves as the upper attachment (in part) for the superficial muscles that are located on the posterior aspect o ...

; from the radial collateral ligament of the

elbow-joint The elbow is the region between the arm and the forearm that surrounds the elbow joint. The elbow includes prominent landmarks such as the olecranon, the cubital fossa (also called the chelidon, or the elbow pit), and the lateral and the med ...

; from a strong

aponeurosis An aponeurosis (; plural: ''aponeuroses'') is a type or a variant of the deep fascia, in the form of a sheet of pearly-white fibrous tissue that attaches sheet-like muscles needing a wide area of attachment. Their primary function is to join muscl ...

which covers its surface; and from the intermuscular septa between it and the adjacent muscles.'' Gray's Anatomy'' 1918, see infobox The fibres end approximately at the middle of the forearm in the form of a flat tendon, which is closely connected with that of the extensor carpi radialis longus, and accompanies it to the wrist; it passes beneath the abductor pollicis longus and extensor pollicis brevis, beneath the extensor retinaculum, and inserts into the lateral dorsal surface of the base of the third metacarpal bone, with a few fibres inserting into the medial dorsal surface of the second metacarpal bone.

Relations

Under the extensor retinaculum the tendon lies on the back of the radius in a shallow groove, to the ulnar side of that which lodges the tendon of the extensor carpi radialis longus, and separated from it by a faint ridge.

Innervation

Like all the muscles in the posterior

forearm The forearm is the region of the upper limb between the elbow and the wrist. The term forearm is used in anatomy to distinguish it from the arm, a word which is most often used to describe the entire appendage of the upper limb, but which in ...

, ECR brevis is supplied by a branch of the

radial nerve The radial nerve is a nerve in the human body that supplies the posterior portion of the upper limb. It innervates the medial and lateral heads of the triceps brachii muscle of the arm, as well as all 12 muscles in the posterior osteofascial comp ...

Function

It is an extensor, and an abductor of the hand at the

wrist In human anatomy, the wrist is variously defined as (1) the carpus or carpal bones, the complex of eight bones forming the proximal skeletal segment of the hand; "The wrist contains eight bones, roughly aligned in two rows, known as the carpal ...

joint A joint or articulation (or articular surface) is the connection made between bones, ossicles, or other hard structures in the body which link an animal's skeletal system into a functional whole.Saladin, Ken. Anatomy & Physiology. 7th ed. McGraw ...

. That is, it serves to manipulate the wrist so that the fingers moves away from the palm. The muscle, like all extensors of the forearm, can be strengthened by exercise that resist its extension; Reverse wrist curls with

dumbbell The dumbbell, a type of free weight, is a piece of equipment used in weight training. It can be used individually or in pairs, with one in each hand. History The forerunner of the dumbbell, halteres, were used in ancient Greece as lifting ...

s can be performed.

Additional images

References

{{Authority control Muscles of the upper limb