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, by the common extensor tendon; from the radial collateral ligament of the

elbow-joint The elbow is the region between the arm, upper 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 epic ...

; from a strong

aponeurosis An aponeurosis (; : aponeuroses) is a flattened tendon by which muscle attaches to bone or fascia. Aponeuroses exhibit an ordered arrangement of collagen fibres, thus attaining high tensile strength in a particular direction while being vulnerable ...

which covers its surface; and from the intermuscular septa between it and the adjacent muscles.''

Gray's Anatomy ''Gray's Anatomy'' is a reference book of human anatomy written by Henry Gray, illustrated by Henry Vandyke Carter and first published in London in 1858. It has had multiple revised editions, and the current edition, the 42nd (October 2020 ...

'' 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 In human anatomy, the extensor pollicis brevis (EPB) is a skeletal muscle on the dorsal side of the forearm. It lies on the medial side of, and is closely connected with, the abductor pollicis longus. The extensor pollicis brevis belongs to t ...

, beneath the extensor retinaculum, and inserts into the lateral dorsal surface of the base of the

third metacarpal bone The third metacarpal bone (metacarpal bone of the middle finger) is a little smaller than the second. The dorsal aspect of its base presents on its radial side a pyramidal eminence, the styloid process, which extends upward behind the capitate; ...

, with a few fibres inserting into the medial dorsal surface of the

second metacarpal bone The second metacarpal bone (metacarpal bone of the index finger) is the longest, and its base the largest, of all the Metacarpus, metacarpal bones.''Gray's Anatomy'' (1918). See infobox. Human anatomy Its base is prolonged upward and medialwar ...

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 used to describe the entire appendage of the upper limb, but which in anatomy, techn ...

, 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 compartment of the ...

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 dumbbells can be performed.

Additional images

References

{{Authority control Muscles of the upper limb