Extensor carpi radialis longus muscle
|Extensor carpi radialis longus|
|Superficial muscles of the foreamr. Extensor carpi radialis longus visible in blue.|
|Transverse section across the wrist and digits. (Ext. carp. rad. long. labeled at center left.)|
|Latin||musculus extensor carpi radialis longus|
|Gray's||subject #125 452|
|Origin:||lateral supracondylar ridge|
|Action:||extensor at the wrist joint, abducts the hand at the wrist|
|Antagonist:||Flexor carpi radialis muscle|
Extensor carpi radialis longus is one of the five main muscles that control movement at the wrist. This muscle is quite long, starting on the lateral side of the humerus, and attaching to the base of the 2nd metacarpal.
As the name suggests, this muscle is an extensor at the wrist joint, and travels along the radial side of the arm, so will also abduct the hand at the wrist. That is, it manipulates the wrist so as to move the hand towards the thumb and away from the palm.
Origin and insertion
It arises from the lower third of the lateral supracondylar ridge of the humerus, from the lateral intermuscular septum, and by a few fibers from the common tendon of origin of the Extensor muscles of the forearm.
The fibers 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. It is inserted into the dorsal surface of the base of the second metacarpal bone, on its radial side.
Being an extensor contained in the forearm, it is innervated by the radial nerve.