Extensor Carpi Radialis Longus Muscle Anatomy

The extensor carpi radialis longus (ECRL), a fusiform muscle, is partly overlapped by the brachioradialis, with which it often blends. It’s one of the three Muscles that extend and abduct or adduct the hand at the wrist joint alongside with extensor carpi radialis brevis and extensor carpi ulnaris.

ECRL is located in the superficial posterior compartment of the forearm, which contains the following muscles:

• Brachioradialis,
• Extensor carpi radialis longus and brevis,
• Extensor digitorum,
• Extensor digiti minimi
• Extensor carpi ulnaris.

See Also: Forearm Muscles Anatomy & Function

Extensor Carpi Radialis Longus Muscle Anatomy

Extensor Carpi Radialis Longus Muscle originates from the lateral supracondylar ridge of the humerus and from the lateral intermuscular septum of arm.

As it passes distally, posterior to the brachioradialis, its tendon is crossed by the abductor pollicis brevis and extensor pollicis brevis. It inserted into the dorsal surface of the base of the second metacarpal bone, on its radial side.

As all the extensors of the wrist, the extensor carpi radialis longus is innervated by the radial nerve (C6 -C7).

Its function is to extend the wrist, also plays a role in wrist abduction (radial deviation).

The tendon of the extensor carpi radialis longus muscle is useful in tendon transfer, such as in correction of finger clawing and restoration of thumb opposition. 

To test the extensor carpi radialis longus, the wrist is extended and abducted with the forearm pronated. If acting normally, the muscle can be palpated inferoposterior to the lateral side of the elbow. Its tendon can be palpated proximal to the wrist.

References & More

1. Clinically Oriented Anatomy – 8th Edition
2. Clinical Anatomy by Regions, Richard S. Snell.
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