M2 Forearm Muscles Attachments, Actions, Innervations

Abductor pollicis longus spinal segments

C6-8

Abductor pollicis longus attachments

from proximal posterior radius, ulna & interosseous membrane to the base of the 1^st metacarpal & trapezium

Abductor pollicis longus innervations

radial nerve

Abductor pollicis longus actions

abducts & extends thumb at carpometacarpal joint & abducts hand at wrist (radial deviation)

Brachioradialis spinal segments

C5-6

Brachioradialis attachments

from the lateral supracondylar ridge of the humerus to the distal radius lateral to the styloid process

Brachioradialis actions

flexes the elbow

Brachioradialis Innervations

radial nerve

Extensor carpi radialis brevis spinal segments

C6-8

Extensor carpi radialis brevis attachments

from the lateral epicondyle of the humerus (common extensor origin) to the base of the 3^rd metacarpal 

Extensor carpi radialis brevis actions

extends & abducts hand at wrist (radial deviation)

Extensor carpi radialis brevis innervation

radial nerve

Extensor carpi radialis longus spinal segments

C6-8

Extensor carpi radialis longus attachments

from the lateral supracondylar ridge of the humerus to the base of the 2^nd metacarpal

Extensor carpi radialis longus actions

extends & abducts hand at wrist (radial deviation) & assists in flexion of the elbow

Extensor carpi radialis longus innervations

radial nerve

Extensor carpi ulnaris spinal segments

C6-8

Extensor carpi ulnaris attachments

from the lateral epicondyle of the humerus (common extensor origin) to the base of the 5^th metacarpal

Extensor carpi ulnaris actions

extends & adducts hand at wrist (ulnar deviation)

Extensor carpi ulnaris innervation

radial nerve

Extensor digitorum spinal segments

C6-8

Extensor digitorum attachments

from the lateral epicondyle of the humerus (common extensor origin) to the extensor expansions of digits 2-5

Extensor digitorum actions

- extends phalanges (primarily at metacarpophalangeal, secondarily at interphalangeal)  & hand at wrist

Extensor digitorum innervation

radial nerve

Extensor digiti minimi spinal segments

C7-8

Extensor digiti minimi attachments

from the lateral epicondyle of the humerus (common extensor origin) to the digital expansion of the 5^th digit

Extensor digiti minimi actions

extends 5^th digit (metacarpophalangeal & interphalangeal)

Extensor digiti minimi innervation

radial nerve

Extensor indicis spinal segments

C7-8

Extensor indicis attachments

from the posterior surface of the ulna & interosseous membrane to the digital expansion of the 2^nd digit

Extensor indicis actions

extends 2^nd digit (metacarpophalangeal & interphalangeal)

Extensor indicis innervation

radial nerve

Extensor pollicis brevis spinal segments

C6-8

Extensor pollicis brevis attachments

from the posterior radial surface & interosseous membrane to the base of the 1^st proximal phalanx

Extensor pollicis brevis actions

extends thumb (metacarpophalangeal) & extends & abducts CMC joint

Extensor pollicis brevis innervations

radial nerve

Extensor pollicis longus spinal segments

C6-8

Extensor pollicis longus attachments

from the middle 1/3^rd of the posterior surface of the ulna & interosseous membrane to the base of the 1^st distal phalanx

Extensor pollicis longus actions

extends thumb (CMC & metacarpophalangeal & interphalangeal)

Extensor pollicis longus innervation

radial nerve

Flexor carpi radialis spinal segments

C6-8

Flexor carpi radialis attachments

from the medial epicondyle (common flexor origin) to the palmar aspect of the base of the 2^nd metacarpal

Flexor carpi radialis actions

flexes & abducts hand at wrist (radial deviation) & may assist in pronation of forearm & flexion of the elbow

Flexor carpi radialis innervation

median nerve

Flexor carpi ulnaris spinal segments

C7-T1

Flexor carpi ulnaris attachments

from the medial epicondyle (common flexor origin) of the humerus & proximal ulnar shaft to the pisiform

Flexor carpi ulnaris actions

flexes & adducts hand at wrist (ulnar deviation) & assists in flexion of the elbow

Flexor carpi ulnaris innervation

ulnar nerve

Flexor digitorum profundus spinal segments

C7-T1

Flexor digitorum profundus attachments

from the anterior proximal two thirds of the ulna & interosseous membrane to the base of the distal phalanges of digits 2-5

Flexor digitorum profundus actions

flexion of digits 2-5 (metacarpophalangeal & distal interphalangeal & proximal interphalangeal), & flexion of hand at wrist

Flexor digitorum profundus innervation

median (anterior interosseous nerve; 2^nd & 3^rd digits) & ulnar (4^th & 5^th digits) nerves

Flexor digitorum superficialis spinal segments

C7-T1

Flexor digitorum superficialis attachments

from the medial epicondyle (common flexor origin) of the humerus to the sides of the middle phalanges of digits 2-5

Flexor digitorum superficialis actions

flexion of digits (metacarpophalangeal & proximal interphalangeal), & hand at wrist

Flexor digitorum superficialis innervations

median nerve

Flexor pollicis longus spinal segments

C7-T1

Flexor pollicis longus attachments

from the anterior surface of the radius & interosseous membrane to the base of the distal phalanx of the thumb

Flexor pollicis longus actions

flexes thumb (metacarpophalangeal & interphalangeal)

Flexor pollicis longus innervations

median nerve (anterior interosseous nerve)

Palmaris longus spinal segments

C7-8

Palmaris longus attachments

from the medial epicondyle of the humerus (common flexor origin) to the palmar aponeurosis

Palmaris longus actions

flexes hand at wrist & tenses palmar fascia

Palmaris longus innervation

median nerve

Pronator quadratus spinal segments

C8-T1

Pronator quadratus attachments

from the anterior surface of the distal ulna to the anterior surface of the distal radius

Pronator quadratus actions

pronates the forearm

Pronator quadratus innervation

median nerve (anterior interosseous nerve)

Pronator teres spinal segment

C6-7

Pronator teres attachments

from the medial epicondyle & ulnar coronoid process to lateral aspect of the radius

Pronator teres actions

pronates & flexes forearm

Pronator teres innervation

median nerve

Supinator spinal segments

C5-6

Supinator attachments

from the lateral epicondyle of the humerus, radial collateral ligament & supinator crest of the ulna to the lateral surface of the proximal radius

Supinator actions

supinates forearm

Supinator innervation

radial nerve