The supinator muscle assists Biceps brachii in supinating the hand, that is turning it over so that the palm faces up. To isolate the supinator muscle, supinate the hand whilst extending the elbow as this takes out the Biceps muscle.


  • Lateral supracondylar ridge of the humerus
  • Posterior part of the ulna


  • Outer surface of the upper third of the radius


  • Supination


  • Posterior interosseous branch of the radial nerve

Daily uses

  • Turning a screwdriver

How can I strengthen it?

  • Supination using a resistance band

Elbow Joint Muscles:

Related Articles

Biceps Brachii

The Biceps brachii crosses both the elbow and shoulder joints. It is a weak flexor of the shoulder joint but is a strong flexor the elbow joint, especially when the forearm is supinated (palm facing...

Triceps Brachii

The Triceps Brachii also assists Latissimus Dorsi in extending the shoulder joint. It contracts strongly during the up phase of a push-up, to straighten the arm.


The Brachioradialis muscle acts to supinate the forearm from a pronated position, when it flexes the elbow. When starting in a supinated position, it acts to pronate the hand as it flexes the elbow.

More Human Muscles: