The extensor carpi radialis longus is one of the five main muscles that control movements on the wrist. This muscle is quite long, which begins on the lateral side of the humerus, and is attached to the base of the second metacarpal bone (metacarpal of the index finger).
The structure of extensor carpi radialis longus muscle
It arises from the lateral supracondylar ridge of the humerus, from the lateral intermuscular septum, and by some fibers from the lateral epicondyle of the humerus.
The fiber terminates at the upper third of the forearm in an upper tendon, which runs along the lateral border of the radius, below the abductor pollicis longus and extensor pollicis brevis; It then passes under the dorsal carpal ligament, where it is in a groove behind the radius and immediately after the styloid process is the extensor carpi radialis brevis.
One of the three muscles of the radial forearm group, it is initially located next to the brachioradialis, but most often forms the tendon. Passing between the brachioradialis and the extensor carpi radialis brevis, this tendon continues in the second tendon compartment in association with the posterior muscle.
It is inserted into the dorsal surface of the base of the second metacarpal bone on its radial side.