Elbow Muscles

The elbow muscles include the triceps brachii, brachioradialis, brachialis, biceps brachii, pronator teres, pronator quadratus, and anconeus. Here we explain the muscles of the elbow and sepcifically the origin (where it starts), insertion, nerves which make it contract and the resulting movements.


What movements are available at the elbow?

Elbow joint bones

The elbow joint consists of the humerus bone (upper arm) and the radius and ulna in the forearm. Movements or joint actions available at the elbow joint are flexion (bending) and extension (straightening). Additionally, pronation (turning inwards) and supination (outwards) are available at the joint between the radius and ulna.

Pronator Teres

Pronator teres elbow muscles

Pronator Teres works the hardest when the elbow flexes whilst the hand simultaneously pronates. Pronation is when you turn your forarm so your palm is face down.

  • Origin: Medial supracondylar ridge of the humerus & medial side of the coronoid process of the ulna.
  • Insertion: Middle 1/3 of the outer surface of the radius
  • Actions: Pronation. Elbow flexion
  • Innervation: Median nerve
  • Daily uses: Turning a screwdriver

Triceps Brachii

Elbow muscles - 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.

  • Origin: Long head – The lower part of the glenoid cavity of the scapula. Lateral head – Upper half of the posterior surface of the humerus. Medial head – Lower 2/3 of the posterior surface of the humerus
  • Insertion: Olecranon process of the ulna
  • Actions: Elbow  extension
  • Innervation: Radial nerve
  • Daily uses: Pushing a door closed
  • Example strengthening exercises: Tricep extension. Overhead tricep extension. Tricep dips
  • Example stretches: Tricep stretch



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.

  • Origin: Lower 2/3 of the lateral supracondylar ridge of the humerus.
  • Insertion: Styloid process of the radius.
  • Actions: Elbow flexion. Pronation. Supination
  • Innervation: Radial nerve.
  • Daily uses: Turning a corkscrew.
  • Example strengthening exercises: Bicep curls using a resistance band.



The Brachialis acts to flex the elbow whether in pronation or supination, along with Biceps Brachii. As Brachialis is attached to the Ulna, which cannot rotate, it is the only true flexor of the elbow.

  • Origin: Lower half of the anterior humerus.
  • Insertion: Coronoid process of the ulna.
  • Actions: Elbow flexion.
  • Innervation: Musculocutaneous nerve.
  • Daily uses: Picking up shopping bags.
  • Example strengthening exercises: Bicep curls using a resistance band.

Biceps Brachii

Biceps brachii

The Biceps brachii crosses both the elbow and shoulder joints. Its action on the shoulder joint is very weak flexion. It works most efficiently in flexing the elbow joint when the forearm is supinated (palm facing up). The bicep curl is the most commonly used exercise to strengthen this muscle.

  • Origin: Long head – top of the glenoid fossa. Short head – coracoid process.
  • Insertion: Bicipital tuberosity of the radius. Bicipital aponeurosis into the deep fascia of the forearm.
  • Actions: Elbow flexion. Supination of the forearm.
  • Innervation: Musculocutaneous nerve.
  • Daily uses: Picking up a shopping bag.
    Biceps curl using a resistance band or dumbbell.
  • Example exercises: Bicep curl.



The Anconeus is one of the small elbow muscles. It works alongside Triceps Brachii in extending the elbow. It also acts to pull the synovial membrane out of the way of the olecranon process when the elbow is extending.

  • Origin: Posterior surface of the lateral condyle of the humerus.
  • Insertion: Posterior surface of the upper ulna and its olecranon process.
  • Actions: Elbow extension.
  • Innervation: Radial nerve.
  • Daily uses: Pushing a door closed.
  • Example strengthening exercises: Tricep extension with a resistance band.
    Overhead triceps extension with a resistance band.
  • Example stretches: Tricep stretch.


Supinator muscle

The supinator muscle is an elbow joint muscle that is used most when your arm is straight and you are turning your forearm outwards. Or to use the correct terminology, extended and supinating.

  • Origin: Lateral epicondyle of the humerus and posterior part of the ulna.
  • Insertion: Lateral surface of the radius.
  • Actions: Supination of the forearm.
  • Innervation: Radial nerve (C6).
  • Daily uses: Unscrewing a screwdriver
  • Example strengthening exercises: Anything that resists forearm supination.
  • Example stretches: Maximal pronation of the forearm.

Pronator Quadratus

Pronator quadratus muscle

The pronator quadratus muscle pronates the forearm as well as helping the triceps muscle extend (straighten) the elbow.

  • Origin: Distal quarter of the anterior side of the ulna.
  • Insertion: Distal quarter of the anterior side of the radius.
  • Actions: Pronation of the forearm
  • Innervation: Median nerve
  • Daily uses: Screwing in a screw with a screwdriver
  • Example stretches: Maximum supination of the forearm.

Which elbow muscles extend (straighten) the elbow?

  • Triceps brachii
  • Anconeus

Which elbow muscles flex (bend) the elbow?

  • Biceps brachii
  • Brachialis
  • Bracioradialis
  • Pronator teres
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