Extensor Carpi Radialis Longus

The extensor carpi radialis longus is a muscle within the superficial compartment of the posterior forearm. Its lateral position within the forearm produces abduction as well as extension at the wrist.

The tendon of the extensor carpi radialis longus passes through the 2nd extensor compartment at the wrist.

• Attachments: Originates from the lateral supracondylar ridge of the humerus and attaches to the base of the second metacarpal.
• Actions: Extension and abduction at the wrist
• Innervation: Radial nerve.
• Blood supply: Radial artery

By TeachMeSeries Ltd (2025)

Fig 1
The muscles in the superficial layer of the posterior forearm.