MUSCLES OF THE FOREARM

Anterior superficial muscles of the forearm

Mnemonic to help remember:

REMEMBER: this is in a Radial-ulnar Direction:

Be Proud Ray Punched u.

B- Brachioradialis muscle

P- Pronator teres muscle

F- Flexor Carpi Radialis muscle

P- Palmaris Longus

F- Flexor Carpi Ulnaris

Pronator Teres Muscle

Origin: Medial epicondyle of the humerus

Insertion: middle third of the lateral surface of the radius.

Innervation: Median nerve

Function: Pronation of the forearm

Flexor Carpi Radialis Muscle

Origin: Medial epicondyle of the humerus

Insertion: Base of metacarpals II and III

Innervation: Median Nerve

Function: Flexes and abducts the wrist

Palmaris Longus Muscle

Origin: Medial epicondyle of the humerus

Insertion: Palmar aponeurosis of the hand.

Innervation: Median nerve

Function: Flexes wrist joint.

Flexor Carpi Ulnaris Muscle

Origin: Medial epicondyle of the humerus, the olecranon and the posterior border of the ulna.

Insertion: pisiform bone and then pisohamate and pisometacarpal ligaments into the hamate and the base of the metacarpal V

Innervation: Ulnar Nerve

Function: Flexes and adducts the wrist joint.

Anterior intermidate muscles of the forearm

Flexor Digitorium Superficialis

Flexor digitorium superficialis

Origin: Medial epicondyle of the humerus and coronoid process of the ulna.

Insertion: with the four long tendons at the base of the middle phalanx of the 2nd to 5th fingers (i.e. index, middle, ring and little fingers).

Innervation: Median Nerve

Function: Flexes proximal interphalangeal joints of the index, middle, ring and little fingers; can also flex metacarpophalangeal joints of the same fingers and the wrist joint.

Anterior deep muscles of the forearm

1. Flexor Digitorium Profundus.

2. Flexor Pollicis Longus.

3. Pronator quadratus muscle.

Flexor Digitorium Profundus muscle

Origin: anterior surface of the ulnar, interosseous membrane

Insertion: base of the distal phalanx of the 2nd to 5th fingers

Innervation: The lateral half is by the median nerve; the medial half is by the ulnar nerve.

Function: flexes interphalangeal joints of the index, middle, ring and little finger; can also flex metacarpophalangeal joints of the same fingers and the wrist joint.

Flexor Pollicis Longus

Origin: Anterior surface of the radius

Insertion: base of the distal phalanx of the thumb

Innervation: Median Nerve

Function: Flexes interphalangeal joint of the thumb.

Pronator Quadratus- deepest muscle of the anterior compartment of the forearm

Origin: Distal part of the anterior surface of the ulna.

Insertion: Anterior surface of the radius

Innervation: Median nerve

Function: Pronation of the forearm

Posterior superficial muscles

Remember: in a radial ulnar direction

Brave Long Brevis Digits Might Unite Again

B- Brachioradialis muscle

L- extensor Carpi Radialis Longus

B- extensor Carpi Radialis Brevis

D- extensor Digitorium

M- extensor digiti Minimi

U- extensor carpi Ulnaris

A- Anconeus

Brachioradialis muscle

Origination: Lateral border of the humerus

insertion: proximal aspect of the styloid process of the radius.

Innervations: Radial nerve

Function: it is the lateral border of the cubical fossa. It aids in flexion, supination and pronation of the forearm.

Extensor carpi Radialis Longus

Origination: lateral supracondylar ridge of the humerus

insertion: dorsal area of the base of the metacarpal II.

Innervation: Radial nerve

Function: elbow joint: it aids in pronation, flexion, dorsiflexion and radial abduction.

Extensor carpi Radialis Brevis

Origination: lateral epicondyle of the Humerus

Insertion: dorsal area of the base of metacarpal II and III.

Innervation: Deep branch of the Radial nerve

Function: Elbow joint: flexion, pronation, radial abduction.

Extensor digitorium muscle

Origin: lateral epicondyle of the humerus

Insertion: dorsal aponeuroses of the 2nd to 5th fingers.

Innervation: Posterior Interosseous Nerve

Function: Extends the index, middle, ring, and little fingers, as well as allows wrist extension.

Extensor Digiti Minimi muscle

Origin: Lateral epicondyle of the humerus

Insertion: Dorsal aponeurosis of the 5th finger.

Innervation: Posterior Interosseous nerve.

Function: Extends the little finger

Extensor Carpi ulnaris muscle

Origin: Lateral epicondyle of the humerus and posterior border of the ulnar

Insertion: Dorsal area of the metacarpal V

Innervation: Posterior Interosseous nerve

Function: Extends and adducts the wrist

Anconeus

Origin: Lateral epicondyle of the humerus

Insertion: Olecranon and proximal posterior surface of the ulna

Innervation: Radial nerve

Function: Abduction of the ulna in pronation; accessory extensor of the elbow joint.

Posterior deep muscles

1. Supinator muscle

2. Abductor Pollicis longus Muscle

3. Extensor Pollicis Brevis

4. Extensor Pollicis Longus

5. Extensor Indicis Muscle

Supinator Muscle:

Origin: Lateral epicondyle of the humerus, supinator crest of the ulna, radial collateral and anular ligaments of the radius.

Insertion: anterior surface of the radius (proximal third)

Innervation: Posterior Interosseous nerve

Function: Aids in supination of the forearm

Abductor Pollicis Longus

Origin: Posterior surface of the ulna, interosseous membrane, posterior surface of the radius

Insertion: base of metacarpal I

Innervation: Posterior Interosseous nerve

Function: Abducts carpometacarpal joint of the thumb

Extensor Pollicis Brevis

Origin: Posterior surface of the radius and the adjacent interosseous membrane.

Insertion: base of the proximal phalanx of the thumb.

Innervation: Posterior interosseous nerve

Function: Extends metacarpophalangeal joint of the thumb; can also extend the carpometacarpal the joint of the thumb

Extensor Pollicis Longus Muscle

Origin: distal half of the posterior surface of the ulna, interosseous membrane.

Insertion: Distal phalanx of the thumb.

Innervation: Posterior Interosseous nerve

Function: Extends interphalangeal joint of the thumb; can also extend carpometacarpal and metacarpophalangeal joints of the thumb.

Extensor Indicis Muscle

Origin: Posterior surface of the ulna and adjacent interosseous membrane.

Insertion: Dorsal aponeurosis of the index finger

Innervation: Posterior Interosseous nerve

NOTE: The posterior interosseous nerve is a continuation of the deep branch of the radial nerve)

Function: Extends the index finger

Arteries and veins in the Posterior compartment of the forearm

1. Posterior Interosseous artery

2. Anterior Interosseous artery

3. Radial artery

Veins in the posterior compartment of the forearm

Deep veins of the posterior compartment generally accompany the arteries. They drain into the brachial veins associated with the brachial artery in the cubital fossa