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Extensor carpi radialis longus muscle
From Wikipedia, the free encyclopedia
| Extensor carpi radialis longus | ||
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| Superficial muscles of the foreamr. Extensor carpi radialis longus visible in blue. | ||
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| 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 | |
| Insertion: | 2nd metacarpal | |
| Artery: | radial artery | |
| Nerve: | radial nerve | |
| Action: | extensor at the wrist joint, abducts the hand at the wrist | |
| Antagonist: | Flexor carpi radialis muscle | |
| Dorlands/Elsevier | m_22/12548862 | |
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.
It initially runs along with brachioradialis, but becomes mostly tendon early on, running between brachioradialis and extensor carpi radialis brevis.
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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.
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.
The muscle, like all extensors of the forearm, can be strengthened by exercise that resist its extension. A wrist roller can be used and reverse wrist curls with dumbbells can performed.
 Bones of left forearm. Posterior aspect. |
 Bones of the left hand. Dorsal surface. |
 Tendons of forefinger and vincula tendina. |
 Cross-section through the middle of the forearm. |
 Posterior surface of the forearm. Deep muscles. |
 Transverse section across distal ends of radius and ulna. |
 The mucous sheaths of the tendons on the back of the wrist. |