Extensor carpi radialis longus is one of the five main muscle

Muscle

Muscle is a contractile tissue of animals 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...

s that control movements at the wrist

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;...

. This muscle is quite long, starting on the lateral side of the humerus, and attaching to the base of the second metacarpal bone (metacarpal of the index finger

Index finger

The index finger, , is the first finger and the second digit of a human hand. It is located between the first and third digits, between the thumb and the middle finger...

).

Function

As the name suggests, this muscle is an extensor at the wrist joint

Joint

A joint is the location at which two or more bones make contact. They are constructed to allow movement and provide mechanical support, and are classified structurally and functionally.-Classification:...

 and travels along the radial side of the arm, so will also abduct (radial abduction) the hand at the wrist. That is, it manipulates the wrist so as to move the hand towards the thumb

Thumb

The thumb is the first digit of the hand. When a person is standing in the medical anatomical position , the thumb is the lateral-most digit...

 (i.e., abduction

Abduction (kinesiology)

Abduction, in functional anatomy, is a movement which draws a limb away from the median plane of the body. It is thus opposed to adduction.-Upper limb:* of arm at shoulder ** Supraspinatus** Deltoid* of hand at wrist...

—away from the mid-position of the hand) and away from the palmar side (i.e., extension

Extension (kinesiology)

In kinesiology, extension is a movement of a joint that results in increased angle between two bones or body surfaces at a joint. Extension usually results in straightening of the bones or body surfaces involved. For example, extension is produced by extending the flexed elbow. Straightening of...

—increased angle between the palm and the front of the forearm).

Origin, course, and insertion

It originates from 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....

, from the lateral intermuscular septum, and by a few fibers from the lateral epicondyle

Lateral epicondyle of the humerus

The lateral epicondyle of the humerus is a small, 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 Extensor muscles. In birds, where the arm is somewhat...

 of the humerus.

The fibres end at the upper third of the forearm in a flat tendon, which runs along the lateral border of the radius, beneath the Abductor pollicis longus and Extensor pollicis brevis; it then passes beneath the dorsal carpal ligament, where it lies in a groove on the back of the radius common to it and the Extensor carpi radialis brevis, immediately behind the styloid process.

One of the three muscles of the radial forearm group

Mobile wad

-External links:* *...

, it initially runs along with brachioradialis, but becomes mostly tendon early on. Passing between brachioradialis and extensor carpi radialis brevis

Extensor carpi radialis brevis muscle

The Extensor carpi radialis brevis is shorter and thicker than the extensor carpi radialis longus. The longus muscle can be found above the distal end of the Extensor carpi radialis brevis.-Origin and insertion:...

, this tendon continues into the second tendon compartment together with the latter muscle.

It is inserted into the dorsal surface of the base of the second metacarpal bone, on its radial side.

Innervation

The extensor carpi radialis longus is a wrist extensor that 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 medial and lateral heads of the triceps brachii muscle of the arm, as well as all 12 muscles in the posterior osteofascial compartment of the forearm and the associated joints and overlying skin.It...

. Though the radial nerve receives contributions from vertebrae levels C5, C6, C7, C8 and T1, studies have shown that the neurons that innervate the extensor carpi radialis longus arise from cervical vertebrae levels C6 and C7. All other major extensor muscles in the superficial layer of the posterior compartment (the Extensor Digitorum, Extensor Carpi Radialis Brevis, Extensor Carpi Ulnaris, and the Extensor Digiti Minimi) are innervated by the posterior interosseous branch of the radial nerve.

Exercises

The muscle, like all extensors of the forearm, can be strengthened

Strength training

Strength training is the use of resistance to muscular contraction to build the strength, anaerobic endurance, and size of skeletal muscles. There are many different methods of strength training, the most common being the use of gravity or elastic/hydraulic forces to oppose muscle contraction...

 by exercise that resist its extension. A wrist roller

Wrist roller

The wrist roller is a device designed for strengthening the wrists together in a rolling-pulling motion. It consists of a bar of varying lengths, with a cord or rope attached, which the user rolls and unrolls. This is resisted by the weight of a mass at the bottom of the cord. Rolled and unrolled,...

 can be used and reverse wrist curls

Wrist curl

The wrist curl is a weight training exercise for developing just the wrist flexor muscles of the forearm. It is therefore an isolation exercise. Ideally, it should be done in combination with the "reverse wrist curl" to ensure equal development of the wrist flexor and wrist extensor muscles.Wrist...

 with dumbbell

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 .-History:...

s can performed.

Additional images