Name

# Extensor Carpi Radialis Longus

Pronunciation

(eks-TEN-sor KAR-pi ra-de-A-lus LONG-gus)

Origin/Proximal Attachment

Lower lateral supracondylar ridge of humerus (below brachioradialis); lateral intermuscular septum of humerus

Insertion/Distal Attachment

Base of 2nd metacarpal

Action/Relevance

Extends the hand at the wristRadially deviates the hand at the wristWeakly flexes the forearm at the elbow4. Weakly supinates the forearm

Innervation

Radial nerve (C6, 7)

Notes

Extensor carpi radialis longus is one of the five main muscles that control movement at the wrist.

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.

This muscle is quite long, starting on the lateral side of the humerus, and attaching to the base of the 2nd metacarpal.

Being an extensor contained in the forearm, it is innervated by the radial nerve.

It initially runs along with brachioradialis, but becomes mostly tendon early on, running between brachioradialis and extensor carpi radialis brevis.

Blood is supplied by the radial artery.