Elbow Joint Muscles / Arm Muscles

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