Posterior Forearm Muscles Flashcards Preview

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Flashcards in Posterior Forearm Muscles Deck (11):
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Brachioradialis Origin? Insertion? Innervation? Action?

O: Proximal 2/3 of lateral supracondylar ridge of humerus

I: Lateral surface of distal end of radius proximal to styloid process

Innervation: Radial nerve (C5,C6,C7)

Action: Relatively weak flexion of forearm, maximal when forearm is in midpronated position.

1

Extensor carpi radialis longus Origin? Insertion? Innervation? Action?

O: Lateral supracondylar ridge of humerus

I: Dorsal aspect of base of 2nd metacarpal

Innervation: Radial nerve (C6,C7)

Action: Extension and radial deviation at the wrist joint

2

Extensor carpi radialis brevis Origin? Insertion? Innervation? Action?

O: Lateral epicondyle of humerus (common extensor origin)

I: Dorsal aspect of base of 3rd metacarpal

Innervation: Deep branch of radial nerve (C7,C8)

Action: Extension and radial deviation at wrist joint; active during fist clenching

3

Extensor digitorum Origin? Insertion? Innervation? Action?

O: Lateral epicondyle of humerus (common extensor origin)

I: Extensor expansions of medial 4 fingers

Innervation: Posterior interosseous nerve, a continuation of the deep branch of the radial nerve (C7,C8)

Action: Extends medial 4 fingers primarily at metacarpophalangeal joints, secondarily at interphalangeal joints

4

Extensor digiti minimi Origin? Insertion? Innervation? Action?

O: Lateral epicondyle of humerus

I: Extensor expansion of 5th finger

Innervation: Posterior interosseous nerve, a continuation of the deep branch of the radial nerve (C7,C8)

Action: Extends 5th finger primarily at metacarpophalangeal joint, secondarily at interphalangeal joint

5

Extensor carpi ulnaris Origin? Insertion? Innervation? Action?

O: Lateral epicondyle of humerus; posterior border of ulna via a shared aponeurosis

I: Dorsal aspect of base of 5th metacarpal

Innervation: Posterior interosseous nerve, a continuation of the deep branch of the radial nerve (C7,C8)

Action: Extension and ulnar deviation at wrist joint (also active during fist clenching)

6

Supinator Origin? Insertion? Innervation? Action?

O: Lateral epicondyle of humerus; radial collateral and anular ligaments; supinator fossa; crest of ulna

I: Lateral, posterior, and anterior surfaces of proximal third of radius

Innervation: Deep branch of radial nerve (C7,C8)

Action: Supinates forearm; rotates radius to turn palm anteriorly or superiorly (if elbow is flexed)

7

Abductor pollicis longus Origin? Insertion? Innervation? Action?

O: Posterior surface of proximal halves of ulna, radius, and interosseous membrane

I: Base of 1st metacarpal

Innervation: Posterior interosseous nerve, a continuation of the deep branch of the radial nerve (C7,C8)

Action: Abducts thumb and extends it at carpometacarpal joint

8

Extensor pollicis longus Origin? Insertion? Innervation? Action?

O: Posterior surface of middle third of ulna and interosseous membrane

I: Dorsal aspect of base of distal phalanx of thumb

Innervation: Posterior interosseous nerve, a continuation of the deep branch of the radial nerve (C7,C8)

Action: Extends distal phalanx of thumb at interphalangeal joint; extends metacarpophalangeal and carpometacarpal joints

9

Extensor pollicis brevis Origin? Insertion? Innervation? Action?

O: Posterior surface of distal third of radius and interosseous membrane

I: Dorsal aspect of base of proximal phalanx of thumb

Innervation: Posterior interosseous nerve, a continuation of the deep branch of the radial nerve (C7,C8)

Action: Extends proximal phalanx of thumb at metacarpophalangeal joint; extends carpometacarpal joint

10

Extensor indicis Origin? Insertion? Innervation? Action?

O: Posterior surface of distal third of ulna and interosseous membrane

I: Extensor expansion of 2nd finger

Innervation: Posterior interosseous nerve, a continuation of the deep branch of the radial nerve (C7,C8)

Action: Extends 2nd finger (enabling its independent extension); helps extend hand at wrist