Forearm Muscles Anatomy

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Anterior Compartment

Superficial layer

MuscleActionOriginInsertionInnervationBlood supply
Flexor carpi ulnaris- Flexion of wrist
- Adduction of wrist
- Humeral head: medial epicondyle of humerus
- Ulnar head: olecranon and posterior border of ulna
- Pisiform bone
- Hook of hamate bone
- 5th metacarpal base
- Ulnar nerve: C7,8- Ulnar artery
Palmaris longus- Flexion of wrist
- Tightens palmar aponeurosis
- Medial epicondyle of humerus- Distal half of flexor retinaculum and palmar aponeurosis- Median nerve: C7,8- Ulnar artery
Flexor carpi radialis- Flexion of wrist
- Abduction of wrist
- Medial epicondyle of humerus- 2nd and 3rd metacarpal base- Median nerve: C6,7- Ulnar artery
Pronator teres- Pronation
- Weak flexion of elbow
- Humeral head: Medial epicondyle of humerus
- Ulnar head: Coronoid process
- Middle of lateral radial surface- Median nerve: C6,7- Ulnar artery

Intermediate layer

MuscleActionOriginInsertionInnervationBlood supply
Flexor digitorum superficialis- Flexion of proximal interphalangeal joints of digits 2-5
- Flexion of metacarpophalangeal joints of digits 2-5
- Flexion of the wrist
- Humero-ulnar head: medial epicondyle of humerus, ulna collateral ligament and coronoid process of ulna.
- Radial head: proximal half of border of radius
- Four tendons attach to the palmar surface of the middle phalanges of digits 2-5- Median nerve: C7,8, T1- Ulnar artery

Deep layer

MuscleActionOriginInsertionInnervationBlood supply
Flexor digitorum profundus- Flexion of distal interphalangeal joints of digits 2-5
- Flexion of metacarpophalangeal joints of digits 2-5
- Flexion of the wrist
- Medial and anterior ulna and interosseous membrane- Four tendons attach to the palmar surface of the distal phalanges of digits 2-5- Lateral half: median nerve (anterior interosseous nerve)
- Medial half: ulnar nerve: C8,T1
- Ulnar artery
- Anterior interosseous artery
Flexor pollicis longus- Flexion of interphalangeal joint of thumb- Anterior surface of radius
- Radial half of interosseous membrane
- Palmar surface of base of distal phalanx of thumb- Median nerve (anterior interrosseous nerve): C7,8 - Anterior interosseous artery
Pronator quadratus- Pronation of forearm
- Distal anterior surface of ulna- Distal anterior surface of radius- Median nerve (anterior interosseous nerve): C7,8- Anterior interosseous artery

 

Posterior Compartment

Superficial layer

MuscleActionOriginInsertionInnervationBlood supply
Brachioradialis- Assists with flexion of elbow when forearm in mid-pronation
- Proximal 2/2 of lateral supracondyle ridge of humerus- Lateral surface of distal radius- Radial nerve: C5,6,7
- Radial recurrent artery
Extensor carpi radialis longus- Extends and abducts wrist- Lateral supracondylar ridge of humerus- Base of 2nd metacarpal- Radial nerve: C6,7- Radial artery
Extensor carpi radialis brevis- Extends and abducts wrist
- Lateral epicondyle of humerus- Base of 3rd metacarpal- Radial nerve: C7,8- Radial artery
Extensor digitorum- Extends digits 2-5
- Extends wrist
- Lateral epicondyle of humerus- Extensor expansions of medial four digits- Posterior interosseous nerve: C7,8- Recurrent and posterior interosseous arteries
Extensor digiti minimi- Extends 5th digit- Lateral epicondyle humerus- Extensor expansion of 5th digit at metacarpophalangeal and interphalangeal joints- Posterior interosseous nerve: C7,8- Recurrent interosseous artery
Extensor carpi ulnaris- Extends and adducts wrist- Lateral epicondyle of humerus
- Posterior border of ulna
- Base of 5th metacarpal- Posterior interosseous nerve: C7,8- Ulnar artery
Anconeus- Assists elbow extension
- Stabilises elbow joint
- Abducts ulna during pronation
- Lateral epicondyle of humerus- Olecranon
- Proximal surface of ulna
- Radial nerve: C7,8,T1- Deep brachial artery (middle collateral branch)
- Recurrent interosseous artery

Deep layer

MuscleActionOriginInsertionInnervationBlood supply
Supinator- Supination
- Lateral epicondyle of humerus
- Radial collateral ligament
- Annular ligament
- Supinator crest of ulna
- Lateral, posterior and anterior surfaces of proximal 1/3 radius- Posterior interosseous nerve: C5,6 - Recurrent interosseous artery
Abductor pollicis longus- Abducts and extends thumb at carpometacarpal joint- Posterior surface of ulna, radius and interosseous membrane- Base of 1st metacarpal- Posterior interosseous nerve: C7,8- Posterior interosseous artery
Extensor pollicis brevis- Extends proximal phalanx of thumb at carpometacarpal joint- Posterior surface of radius and interosseous membrane- Base of proximal phalanx of thumb- Posterior interosseous nerve: C7,8- Posterior interosseous artery
Extensor pollicis longus- Extends distal phalanx of thumb at carpometacarpal and interphalangeal joints- Posterior surface of middle 1/3 of ulna and interosseous membrane- Base of distal phalanx of thumb- Posterior interosseous nerve: C7,8- Posterior interosseous artery
Extensor indicis- Extends 2nd digit -Posterior surface of ulna and interosseous membrane- Extensor expansion of 2nd digit- Posterior interosseous nerve: C7,8- Posterior interosseous artery