Abductor Pollicis Longus

Origin:  

Posterior surfaces of ulna, radius and interosseous membrane

Insertion:

Base of 1st metacarpal

Action:

Abducts thumb and extends it at carpometacarpal joint

Extensor Pollicis Longus

The tendon of Extensor Pollicis Longus can be seen on the radial side of the wrist, at the base of the thumb where it forms the lower border of the 'anatomical snuffbox' a triangular shape between two tendons.

Origin

• Upper posterior surface of the ulna

Insertion

• Base of the distal phalanx of the thumb

Actions

• Extension of the wrist
  
• Extension of the thumb

Daily uses

• Releasing your grip on an object

Flexor Carpi Radialis

Flexor Carpi Radialis crosses the elbow joint and so is also a weak elbow flexor.

Origin

• Medial epicondyle of the humerus

Insertion

• Base of the 2nd and 3rd metacarpals

Actions

• Flexion of the wrist
  
• Radial deviation of the wrist

Daily uses

• Pulling rope towards you

Flexor Carpi Ulnaris

Flexor carpi ulnaris is one of the wrist flexor muscles of the front (palmar) aspect of the forearm. It also helps extensor carpi ulnaris to ulnar deviate the wrist.

Origin

• Medial epicondyle of the humerus

Insertion

• Base of the 5th metacarpal
  
• Pisiform and hook of hamate

Actions

• Flexion of the wrist
  
• Ulnar deviation (adduction) of the wrist

Daily uses

• Pulling rope towards you

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

Daily uses

• Picking up a shopping bag

Anconeus

The Anconeus 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

Daily uses

• Pushing a door closed

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

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

Daily uses

• Turning a corkscrew

Extensor Carpi Radialis Brevis

Extensor Carpi Radalis Brevis is the shorter of the two extensor carpi radialis muscles which are found in the forearm and extend the wrist. The word brevis means short in latin. 

Origin

• Lateral epicondyle of the humerus

Insertion

• Base of the 3rd metacarpal (dorsal side)

Actions

• Extension of the wrist
• Radial deviation (abduction) of the wrist

Daily uses

• Typing

Extensor Carpi Radialis Longus

Extensor Carpi Radialis Longus is, as the name suggests, the longer of the two extensor carpi radialis muscles as its origin is the ridge above the lateral epicondyle of the humerus, unlike the other wrist extensors which attach to the epicondyle itself.

Origin

• Lateral supracondylar ridge of the humerus

Insertion

• Base of the 2nd metacarpal (dorsal side)

Actions

• Extension of the wrist
• Radial deviation (abduction) of the wrist

Daily uses

• Typing

Extensor Carpi Ulnaris

Extensor carpi ulnaris is located on the back (dorsum) of the forearm amongst the other wrist extensors. This is the only muscle responsible for ulnar deviation (moving the hand sideways in the direction of the little finger).

Origin

• Lateral epicondyle of the humerus

Insertion

• Base of the 5th metacarpal (dorsal side)

Actions

• Extension of the wrist
• Ulnar deviation (adduction) of the wrist

Daily uses

• Accelerating a motorbike

Extensor Digitorum Communis

Extensor Digitorum Communis is sometimes simply referred to as Extensor Digitorum. It is one of the extensor muscles of the wrist, found in the forearm.

Origin

• Lateral epicondyle of the humerus

Insertion

• Splits into 4 tendons which insert to the bases of the 2nd and 3rd Phalanges of the four fingers

Actions

• Extension of the wrist
• Extension of the fingers

Daily uses

• Pulling the hand back and straightening the fingers to wave

Flexor Digitorum Superficialis

Flexor Digitorum Superficialis is sometimes also known as Flexor Digitorum Sublimis.

Origin

• Medial epicondyle of the humerus
• Medial coronoid process
• Radial tuberosity

Insertion

• Splits into 4 tendons which insert to the sides of the middle Phalange of the four fingers

Actions

• Flexion of the wrist
• Flexion of the fingers

Daily uses

• Making a fist

Coracobrachialis

Origin:

Tip of coracoid process of scapula

Insertion:

Middle third of medial surface of humerus

Action:

Helps to flex and adduct arm

Extensor Pollicis Brevis

Origin:

Posterior surfaces of radius and interosseous membrane

Insertion:

Base of proximal phalanx of thumb

Action:

Extends proximal phalanx of thumb at carpometacarpal joint

Flexor Pollicis Longus

The word pollicis refers to the thumb and so the flexor pollicis longus is the long muscle which flexes the thumb!

Origin

• Middle anterior surface of the radius

Insertion

• Base of the distal phalanx of the thumb

Actions

• Flexion of the thumb 
  
• Flexion of the wrist

Daily uses

• Gripping something tightly

Palmaris Longus

Origin: Medial epicondyle of humerus

Insertion: Distal half of flexor retinaculum and palmar aponeurosis

Action: Flexes hand (at wrist) and tightens palmar aponeurosis

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

Actions

• Pronation

Daily uses

• Turning a screwdriver

Pronator Teres

Pronator Teres works the hardest when the elbow is flexing and 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

Daily uses

• Turning a screwdriver

Supinator 

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.

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.