Extensor carpi radialis brevis
Musculus extensor carpi radialis brevis
Also known as: ECRB
A wrist extensor from the common extensor origin to the base of the 3rd metacarpal. It is the tendon most often involved in tennis elbow.
Overview
ECRB arises from the lateral epicondyle (common extensor origin) and the radial collateral ligament. It runs deep to ECRL in the 2nd compartment and inserts on the base of the 3rd metacarpal, the most central insertion of the wrist extensors. That makes it the purest wrist extensor, with little deviation, and an important stabiliser during gripping. It is supplied by the deep branch of the radial nerve before that branch enters supinator.
Anatomy
- Origin
Lateral epicondyle of the humerus (common extensor origin).
- Insertion
Dorsal surface of the base of the 3rd metacarpal.
- Action
Extension and (weak) abduction of the wrist.
- Innervation
Deep branch of the radial nerve.
- Nerve roots
C7–C8
- Arterial supply
Radial artery and radial recurrent artery.
Function
- Extends the wrist
- Assists abduction
- Stabilises the wrist during gripping
Clinical significance
Lateral epicondylitis
Microtears and angiofibroblastic degeneration at the ECRB origin are the pathological core of tennis elbow. Treatment is load management, eccentric exercise, a counterforce brace, and rarely surgical release.
Compiled from standard anatomy and physiology references — see the Muscular System sources. For education only; not medical advice.