Elbow joint muscles / Arm Muscles

Biceps Brachii / Brachialis / Brachioradialis / Triceps Brachii / Anconeus / Supinator /
Pronator Teres / Pronator Quadratus
Biceps Brachii
The Biceps brachii crosses both the elbow and shoulder joints. Its action on the shoulder joint is very
weak flexion.
The Biceps brachii 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

Musculocutaneus nerve
Daily uses

Picking up a shopping bag
Brachialis
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

Flexion of the elbow
Innervation

Musculocutaneous nerve
Daily uses

Picking up shopping bags
Brachioradialis
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
Triceps Brachii Muscle
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 - 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

Extension of the elbow
Innervation

Radial nerve
Daily uses

Pushing a door closed
Anconeus
The Anconeus works alongside Triceps Brachii in extending the elbow. It also atcs 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
Supinator Muscle
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
Origin

Lateral supracondylar ridge of the humerus

Posterior part of the ulna
Insertion

Outer surface of the upper third of the radius
Actions

Supination
Innervation

Posterior interosseous branch of the radial nerve
Daily uses

Turning a screwdriver
Pronator Teres
Pronator Teres works the hardest when the elbow is flexing the hand simultaneously pronating.
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
Pronator Quadratus
Pronator Quadratus works in conjunction with Triceps Brachii during pronation with elbow
extension.
Origin

Lower quater of the anterior surface of the ulna
Insertion

Lower quarter of the anterior side of the radius
Actions

Pronation
Innervation

Median nerve
Daily uses

Turning a screwdriver