Forearm And Hand Muscles

Front 1

Extensor indicis

Back 1

O: posterior surface of ulna and interosseous membrane

I: tendon of extensor digitorum at level of 2nd metacarpal

A: extend and adduct 2nd finger; assist to extend wrist

I: radial nerve C6, 7, 8

Front 2

Extensor pollicis longus

Back 2

O: posterior surface of ulna and interosseous membrane

I: base of distal phalanx of thumb

A: extend thumb; abduct wrist

I: radial nerve C6, 7, 8

Front 3

Extensor pollicis brevis

Back 3

O: posterior surface of radius and interosseous membrane

I: base of proximal phalanx of thumb

A: extend thumb; abduct wrist

I: radial nerve C6, 7, 8

Front 4

Abductor pollicis longus

Back 4

O: posterior surface of radius and ulna and interosseous membrane

I: base of 1st metacarpal

A: abduct and extend thumb; abduct wrist

I: radial nerve C6, 7, 8

Front 5

Supinator

Back 5

O: lateral epicondyle of humerus, radial collateral ligament, annular ligament, and supinator crest of ulna

I: anterior, lateral surface of radial shaft

A: supinate forearm

I: radial nerve C5, 6, 7

Front 6

Extensor digitorum

Back 6

O: lateral epicondyle of humerus

I: bases of middle and distal phalanges of fingers 2-5

A: extend fingers 2-5; assist to extend wrist

I: radial nerve C6, 7, 8

Front 7

Extensor carpi ulnaris

Back 7

O: lateral epicondyle of humerus

I: base of 5th metacarpal

A: extend and adduct wrist

I: radial nerve C6, 7, 8

Front 8

Extensor carpi radialis brevis

Back 8

O: lateral epicondyle of humerus

I: base of 3rd metacarpal

A: extend and abduct wrist; assist to flex elbow

I: radial nerve C6, 7, 8

Front 9

Extensor carpi radialis longus

Back 9

O: distal lateral supracondylar ridge of humerus

I: base of 2nd metacarpal

A: extend and abduct wrist; assist to flex elbow

I: radial nerve C5, 6, 7, 8

Front 10

Brachioradialis

Back 10

O: distal lateral supracondylar ridge of humerus

I: styloid process of radius

A: flew elbow; assist to probate and supinate forearm when these movements are restricted

I: radial nerve C5, 6

Front 11

Pronator quadratus

Back 11

O: medial and anterior surface of distal ulna

I: lateral and anterior surface of distal radius

A: pronate forearm

I: medial nerve C7, 8, T1

Front 12

Flexor pollicis longus

Back 12

O: anterior surface of radius and interosseous membrane

I: base of distal phalanx of thumb

A: flex thumb; assist to flex wrist

I: median nerve C6, 7, 8, T1

Front 13

Flexor digitorum profundus

Back 13

O: anterior and medial surface of proximal ulna

I: bases of distal phalanges (palmar surface) of fingers 2-5

A: flex 2-5 fingers at DIP; assist to flex wrist

I:

-2 and 3 digits = median nerve C7, 8, T1

-4 and 5 digits = ulnar nerve C7, 8, T1

Front 14

Flexor digitorum superficialis

Back 14

O: medial epicondyle of humerus, ulnar collateral ligament, coronoid process of ulna, interosseous membrane, and proximal shaft of radius

I: sides of middle phalanges of fingers 2-5

A: flex 2-5 fingers at PIP; flex wrist

I: median nerve C7, 8, T1

Front 15

Flexor carpi ulnaris

Back 15

O:

-humeral head = medial epicondyle of humerus

-ulnar head = olecranon process

I: pisiform, hook of hamate, and base of 5th metacarpal

A: flex and adduct wrist; assist to flex elbow

I: ulnar nerve C7, 8, T1

Front 16

Palmaris longus

Back 16

O: medial epicondyle of humerus

I: flexor retinaculum and palmar aponeurosis

A: tense palmar fascia; flex wrist; assist to flex elbow

I: median nerve C6, 7, 8, T1

Front 17

Flexor carpi radialis

Back 17

O: medial epicondyle of humerus

I: bases of 2nd and 3rd metacarpals

A: flex and abduct wrist; assist to flex elbow

I: median nerve C6, 7, 8

Front 18

Pronator teres

Back 18

O: medial epicondyle of humerus and coronoid process of ulna

I: lateral surface of radius

A: pronate forearm; assist to flex elbow

I: median C6, 7

Front 19

Lumbricals

Back 19

O: surfaces of flexor digitorum profundus (FDP) tendons

I: extensor aponeurosis on dorsal surface of phalanges 2-5

A: extend 2-5 fingers at interphalangeal joints; flex 2-5 fingers at metacarpophalangeal joints

I:

-2nd and 3rd fingers = median nerve C8, T1

-4th and 5th fingers = ulnar nerve C8, T1

Front 20

Palmar interossei

Back 20

O: base of 1st, 2nd, 4th, and 5th metacarpals

I: base of proximal phalanx of the related finger and extensor aponeurosis

A: adduct 1st, 2nd, 4th, and 5th fingers toward 3rd finger; assist to flex 1st, 2nd, 4th, and 5th fingers at metacarpophalangeal joints and extend them at interphalangeal joints

I: ulnar nerve C8, T1

Front 21

Dorsal interossei

Back 21

O: adjacent sides of all metacarpals

I: base of proximal phalanx of 2-4 fingers and extensor aponeurosis

A: abduct 2-4 fingers at metacarpophalangeal joints; assist to flex 2-4 fingers at metacarpophalangeal joints and extend at interphalangeal joints

I: ulnar nerve C8, T1

Front 22

Opponens digiti minimi

Back 22

O: hook of hamate and flexor retinaculum

I: shaft of 5th metacarpal (ulnar surface)

A: opposition of 5th finger at carpometacarpal joint

I: ulnar nerve C8, T1

Front 23

Flexor digiti minimi brevis

Back 23

O: hook of hamate and flexor retinaculum

I: base of proximal phalanx of 5th finger (palmar surface)

A: flex 5th finger; assist in opposition of 5th finger towards thumb

I: ulnar nerve C8, T1

Front 24

Abductor digiti minimi

Back 24

O: pisiform and tendon of flexor carpi ulnaris (FCU)

I: base of proximal phalanx of 5th finger (ulnar surface)

A: abduct 5th finger; assist in opposition of 5th finger towards thumb

I: ulnar nerve C8, T1

Front 25

Adductor pollicis

Back 25

O: capitate and 2nd + 3rd metacarpals

I: base of proximal phalanx of thumb

A: adduct thumb; assist to flex thumb

I: ulnar nerve C8, T1

Front 26

Opponens pollicis

Back 26

O: flexor retinaculum and tubercle of trapezium

I: entire length of 1st metacarpal bone (radial surface)

A: opposition of thumb at carpometacarpal joint

I: median nerve C8, T1

Front 27

Flexor pollicis brevis

Back 27

O:

-superficial head = flexor retinaculum

-deep head = trapezium, trapezoid, and capitate

I: base of proximal phalanx of thumb

A: flex thumb; assist in opposition of thumb

I:

-superficial head = median nerve C8, T1

-deep head = ulnar nerve C8, T1

Front 28

Abductor pollicis brevis

Back 28

O: flexor retinaculum, trapezium, and scaphoid tubercle

I: base of proximal phalanx of thumb

A: abduct thumb; assist in opposition of thumb

I: median nerve C8, T1

Front 29

What forearm muscles are superficial “extensor, supinator” muscles?

Back 29

-Brachioradialis

-Extensor carpi radialis longus

-Extensor carpi radialis brevis

-Extensor digitorum

-Extensor carpi ulnaris

Front 30

What forearm muscles are superficial “flexor, pronator” muscles?

Back 30

-Pronator teres

-Flexor carpi radialis

-Palmaris longus

-Flexor carpi ulnaris

Front 31

What forearm muscles are intermediate “flexor, pronator” muscles?

Back 31

-Flexor digitorum superficialis

Front 32

What forearm muscles are deep “flexor, pronator” muscles?

Back 32

-Flexor digitorum profundus

-Flexor pollicis longus

-Pronator quadratus

Front 33

What muscles make up the thenar eminence?

Back 33

-Abductor pollicis brevis

-Flexor pollicis brevis

-Opponens pollicis

Front 34

What muscles make up the hypothenar eminence?

Back 34

-Abductor digiti minimi

-Flexor digiti minimi brevis

-Opponens digiti minimi

Front 35

What muscles do elbow flexion?

Back 35

-Biceps brachii

-Brachialis

-Brachioradialis

-Pronator teres (assist)

-Flexor carpi ulnaris (assist)

-Palmaris longus (assist)

-Flexor carpi radialis (assist)

- Extensor carpi radialis longus (assist)

-Extensor carpi radialis brevis (assist)

Front 36

What muscles do elbow extension?

Back 36

-Triceps brachii

-Aconeus