Extensor Carpi Radialis Brevis Detail

musculus extensor carpi radialis brevis detail

The ECRB is the most clinically important of the wrist extensors — it produces pure wrist extension without radial or ulnar deviation, optimising grip mechanics. It is the primary tendon involved in lateral epicondylitis (tennis elbow).

Nerve: Posterior interosseous nerve (PIN, C7, C8) Blood Supply: Radial recurrent artery Region: Forearm

Anatomical Data

Origin, Insertion & Supply

Origin	Lateral epicondyle — from the common extensor origin, just medial to ECRL
Insertion	Base of the third metacarpal — dorsal surface
Nerve Supply	Posterior interosseous nerve (PIN, C7, C8)
Blood Supply	Radial recurrent artery

Biomechanics

Function & Actions

Actions	Extends the wrist — equal radial and ulnar contribution, producing pure dorsiflexion; The most important wrist extensor for grip

Clinical Relevance

Clinical Notes

ECRB is the primary tendon affected in tennis elbow — the degenerative change (angiofibroblastic hyperplasia) occurs at the ECRB origin on the lateral epicondyle. The Nirschl procedure removes the degenerate ECRB origin. ECRB is also the primary recipient of tendon transfers in radial nerve palsy reconstruction.

Palpation

Palpated on the dorsoradial forearm during resisted pure wrist extension.

Pathology

Common Injuries & Conditions

ECRB Tendinopathy in Tennis Elbow

Degenerative angiofibroblastic change at the ECRB origin on the lateral epicondyle producing lateral elbow pain with grip and wrist extension, the most common cause of tennis elbow.