EN | DE | PT Contact How to study Login Register

Register now and grab your free ultimate anatomy study guide!

Radial muscles of the forearm

The radial musculature consists of three muscles located at the lateral forearm. They all run from or near the lateral epicondyle of the humerus to the wrist.

As their bellies and tendons lie superficially, they can be easily palpated.

Anatomy and supply

The three radial muscles are described below. 

Extensor carpi radialis longus & brevis - dorsal view

Brachioradialis muscle

This muscle originates at the lateral supracondylar ridge (between the brachialis and lateral head of the triceps) and the lateral intermuscular septum of the humerus and inserts at the styloid process of the radius. This powerful muscle is mainly responsible for the lateral contour of the elbow and forearm.

Extensor carpi radialis longus

The ECRL has its origin slightly below at the lateral supracondylar ridge of the humerus and inserts distally at the posterior side of the base of the second metacarpal bone. The majority of this muscle lies underneath the brachioradialis.

Extensor carpi radialis brevis

The ECRB arises from the common extensor tendon of the superficial extensors at the lateral epicondyle of the humerus and attaches to the posterior side of the base of the third metacarpal bone.


Radial nerve - ventral view

Radial nerve - ventral view

All radial muscles are supplied by the radial nerve (C5-C8) which courses between the brachioradialis and brachialis to the elbow and there divides into a deep branch and a superficial branch at the height of the radial head.

The superficial branch uses the brachioradialis as a guiding structure to reach the wrist joint and arrives at the dorsum of the hand.

In contrast, the deep branch penetrates the supinator muscle and continues to the extensors of the forearm. It is important to notice that the branches supplying the brachioradialis and extensor carpi radialis longus branch off before the division of the radial nerve, whereas the nerve supplying the extensor carpi radialis brevis, the posterior interosseus nerve, arises just after the division.

Recommended video: Radial Forearm Muscles
Origins, insertions, innervation and functions of the radial forearm muscles.


The radial musculature supports movements of the elbow, hand and radioulnar joints.

Brachioradialis - pronated forearm

Brachioradialis - pronated forearm

  • The brachioradialis is a strong flexor muscle of the elbow joint. Additionally it can supinate or pronate the forearm to the anatomical neutral position, but not further, which is why the flexion of the elbow is the most powerful in a neutrally positioned arm.

Extensor carpi radialis longus - dorsal view

Extensor carpi radialis longus - dorsal view

  • In contrast, both the extensor carpi radialis longus and brevis are rather poor flexors of the elbow. Their main function is the dorsal extension and radial abduction of the wrist joint. They also contribute to a strong fist closure by previously stretching the flexor muscles of the hand and fingers.

Extensor carpi radialis brevis - dorsal view

Extensor carpi radialis brevis - dorsal view

Clinical note

In neurological examinations, the brachioradialis serves as a reference muscle for the nerve roots C5 and C6, by means of the brachioradialis reflex.

It is performed by striking on the tendon at the distal end of the radius causing a flexion of the elbow joint. A weakened or absent reflexive contraction can be of diagnostic relevance for a lesion at the nerve roots. An alternative or addition to the brachioradialis reflex is the biceps reflex.

In many sports and occupational activities, a permanent extension of the wrist joint is demanded (e.g. driving of screws or painting the wall). In the long term, continuous false strain can lead to microtraumata, inflammation or tears in the tendon of the extensor muscles of the wrist joint.

The tendon of the extensor carpi radialis brevis is particularly prone to these lesions (lateral epicondylitis) causing pain at the lateral part of the elbow and a reduced ability to extend one’s hand. As tennis players are especially affected by this condition, it is also referred to as the tennis elbow.

Get me the rest of this article for free
Create your account and you'll be able to see the rest of this article, plus videos and a quiz to help you memorize the information, all for free. You'll also get access to articles, videos, and quizzes about dozens of other anatomy systems.
Create your free account ➞
Show references


  • M. Schünke/E. Schulte/U. Schumacher: Prometheus – LernAtlas der Anatomie – Allgemeine Anatomie und Bewegungssystem, 2nd edition, Thieme Verlag (2007), p. 310-311
  • J. E. Muscolino: The muscular system manual – The skeletal muscles of the human body, 2nd edition, Elsevier Mosby (2005), p. 586-588, 603-608
  • W. Kahle/M. Frotscher: Taschenatlas Anatomie – Band 3 – Nervensystem und Sinnesorgane, 10nd edition, Thieme Verlag (2009), p. 82-83
  • I. Reuter: Radiusperiostreflex, Lexikon Orthopädie und Unfallchirurgie, Springer Medizin (link) S. D. Waldman: Atlas of common pain syndromes, Saunders (2002), p. 98-100


  • Achudhan Karunaharamoorthy


  • Extensor carpi radialis longus & brevis - dorsal view - Yousun Koh 
  • Radial nerve - ventral view - Yousun Koh 
  • Brachioradialis - pronated forearm - Yousun Koh 
  • Extensor carpi radialis longus - dorsal view - Yousun Koh 
  • Extensor carpi radialis brevis - dorsal view - Yousun Koh 
© Unless stated otherwise, all content, including illustrations are exclusive property of Kenhub GmbH, and are protected by German and international copyright laws. All rights reserved.

Related Atlas Images

Extensors of the forearm

Radius and ulna

Flexors of the forearm

Continue your learning

Article (You are here)
Other articles
Well done!

Register now and grab your free ultimate anatomy study guide!

Create your free account.
Start learning anatomy in less than 60 seconds.