Posterior Forearm Muscles (Quiz 2/Exam 2)

Question 1

The extensor muscles are on the __________________________ compartment of the forearm

Answer 1

posterior (extensor-supinator)

Question 2

The extensor muscles are on the posterior (extensor-supinator) compartment of the forearm. They are all innervated by branches of the….

Answer 2

radial n.

Question 3

The extensor muscles are on the posterior (extensor-supinator) compartment of the forearm. What are the 3 functional groups?

Answer 3

1) muscles that extend and abduct or adduct the hand at the wrist joint
2) muscles that extend the medial 4 fingers
3) muscles that extend or abduct the thumb

Question 4

What are the 3 muscles that extend and abduct or adduct the hand at the wrist joint?

Answer 4

1) extensor carpi radialis longus
2) extensor carpi radialis brevis
3) extensor carpi ulnaris

Question 5

What are the 3 muscles that extend the medial 4 fingers?

Answer 5

1) extensor digitorum
2) extensor indicis
3) extensor digiti minimi

Question 6

What are the 3 muscles that extend or abduct the thumb?

Answer 6

1) abductor pollicis longus
2) extensor pollicis brevis
3) extensor pollicis longus

Question 7

What are the 6 superficial extensors?

Answer 7

1) extensor carpi radialis brevis
2) extensor digitorum
3) extensor digit minimi
4) extensor carpi ulnaris
5) brachioradialis
6) extensor carpi radialis longus

Question 8

4 of the superficial extensors
1) extensor carpi radialis brevis
2) extensor digitorum
3) extensor digit minimi
4) extensor carpi ulnaris
are all attached proximally by a common extensor tendon to the __________ epicondyle

Answer 8

lateral

Question 9

The proximal attachment of the brachioradialis and extensor carpi radialis longus is to the lateral ________________ ridge of the humerus and adjacent lateral inter-muscular system

Answer 9

supraepicondylar

Question 10

What is the origin/proximal attachment of the brachioradialis?

Answer 10

proximal 2/3 of supra-epicondylar ridge of humerus

Question 11

What is the insertion/distal attachment of the brachioradialis?

Answer 11

lateral surface of distal end of radius proximal to styloid process

Question 12

What innervates the brachioradialis?

Answer 12

radial n.

Question 13

What are the actions of the brachioradialis?

Answer 13

relatively weak flexion of forearm (maximal when forearm is mid-pronated, aka thumb facing ceiling/perpendicular to ceiling)

Question 14

The _________________ and the ______________ are the only muscles of the posterior forearm compartment that do not cross and therefore are incapable of acting at the wrist

Answer 14

brachioradialis, supinator

Question 15

What is the origin/proximal attachment for the extensor carpi radialis longus (ECRAL)?

Answer 15

lateral supra-epicondylar ridge of humerus

Question 16

What is the insertion/distal attachment of the extensor carpi radialis longus (ECRAL)?

Answer 16

dorsal aspect of base of 2nd metacarpal

Question 17

What innervates the extensor carpi radialis longus (ECRAL)?

Answer 17

deep branch of the radial n.

Question 18

What are the actions of the extensor carpi radialis longus (ECRAL)?

Answer 18

-extend and abduct the arm at wrist joint
-extensor carpi radialis longus (ECRAL) is active during fist clenching

Question 19

What is the origin/proximal attachment of the extensor carpi radialis brevis (ECRB)?

Answer 19

lateral epicondyle of the humerus (common extensor origin)

Question 20

What is the insertion/distal attachment of the extensor carpi radialis brevis (ECRB)?

Answer 20

dorsal aspect of base of the 3rd metacarpal

Question 21

What innervates the extensor carpi radialis brevis (ECRB)?

Answer 21

deep branch of the radial n.

Question 22

What are the actions of the extensor carpi radialis brevis (ECRB)?

Answer 22

-extend and abduct the hand at the wrist joint
-extensor carpi radialis brevis (ECRB) is active during fist clenching

Question 23

What is the origin/proximal attachment for the extensor digitorum?

Answer 23

lateral epicondyle of humerus (common extensor origin)

Question 24

What is the insertion/distal attachment of the extensor digitorum?

Answer 24

extensor expansions of medial 4 digits (sides of fingers)

Question 25

What innervates the extensor digitorum?

Answer 25

deep branch of the radial n.

Question 26

What are the actions of the extensor digitorum?

Answer 26

extends medial 4 digits primarily at the metacarpophalangeal (MCP) joints, secondarily as interphalangeal (IP) joints

Question 27

What is the origin/proximal attachment of the extensor digiti minimi?

Answer 27

lateral epicondyle of the humerus (common extensor origin)

Question 28

What is the insertion/distal attachment of the extensor digiti minimi?

Answer 28

extensor expansion of 5th digit

Question 29

What innervates the extensor digiti minimi?

Answer 29

deep branch of radial n.

Question 30

What are the actions of the extensor digit minimi?

Answer 30

extends 5th digit primarily at MCP joint and secondarily at IP joint

Question 31

What are the origins/proximal attachments for the extensor carpi ulnaris (ECU)?

Answer 31

-lateral epicondyle of humerus -posterior border of ulna via a shared aponeurosis

Question 32

What is the insertion/distal attachment for the extensor carpi ulnaris (ECU)?

Answer 32

dorsal aspect of the base of the 5th metacarpal

Question 33

What innervates the extensor carpi ulnaris (ECU)?

Answer 33

deep branch of radial n.

Question 34

What are the actions of the extensor carpi ulnaris (ECU)?

Answer 34

-extends and adducts the hand at wrist joint -active during fist clenching

Question 35

Which muscles are active during fist clenching?

Answer 35

-extensor carpi radialis longus -extensor carpi radialis brevis -extensor carpi ulnaris

Question 36

What muscles have distal attachments to the metacarpals? TEST Q

Answer 36

1st metacarpal) abductor pollicis longus 2nd) extensor carpi radialis longus 3rd) extensor carpi radialis brevis 4th) nothing 5th) extensor carpi ulnaris

Question 37

What muscles have attachments to digit expansions? TEST Q

Answer 37

1st expansion) extensor digitorum (medial 4 digit expansions) 2nd) extensor indicis 3rd) nothing 4th) nothing 5th) extensor digit minini

Question 38

What are the origins/proximal attachments of the supinator?

Answer 38

-lateral epicondyle of the humerus -radial collateral and anular ligaments -supinator fossa -crest of ulna

Question 39

What are the insertions/distal attachments for the supinator?

Answer 39

lateral, posterior, and anterior surfaces of the proximal 3rd of radius

Question 40

What innervates the supinator?

Answer 40

deep branch of radial n.

Question 41

What are the actions of the supinator?

Answer 41

-supinates forearm -rotates radius to turn palm anteriorly or superiorly (if elbow is flexed)

Question 42

What is the origin/proximal attachment for the extensor indicis?

Answer 42

posterior surface of distal 3rd of ulna and interosseous membrane

Question 43

What is the insertion/distal attachment of the extensor indicis?

Answer 43

extensor expansion of 2nd digit

Question 44

What innervates the extensor indicis?

Answer 44

deep branch of radial n.

Question 45

What are the actions of the extensor indicis?

Answer 45

-extends 2nd digit (enabling its independent extension) -helps extend hand at the wrist

Question 46

What is the origin/proximal attachment of the abductor pollicis longus?

Answer 46

posterior surface of the proximal halves of the ulna, radius, and interosseous membrane

Question 47

What is the insertion/distal attachment of the abductor pollicis longus?

Answer 47

base of 1st metacarpal

Question 48

What innervates the abductor pollicis longus?

Answer 48

deep branch of the radial n.

Question 49

What is the action of the abductor pollicis longus?

Answer 49

abducts thumb and extends it at the CMC joint

Question 50

What is the origin/proximal attachment of the extensor pollicis longus?

Answer 50

posterior surface of the middle 3rd of ulna and interosseous membrane longuuuuus =uuuuulna

Question 51

What is the insertion/distal attachment of the extensor pollicis longus?

Answer 51

dorsal aspect of the base of the distal phalanx of the thumb

Question 52

What innervates the extensor pollicis longus?

Answer 52

deep branch of the radial n.

Question 53

What are the actions of the extensor pollicis longus?

Answer 53

-extends distal phalanx of thumb at IP joint -extends MCP and CMC joints

Question 54

What is the origin/proximal attachment for the extensor pollicis brevis?

Answer 54

posterior surface of the distal 3rd of the radius and interosseous membrane rrrrrrrrrrrrrrradius = brrrrrrrrevis

Question 55

What is the insertion/distal attachment of the extensor pollicus brevis?

Answer 55

dorsal aspect of the base of the proximal phalanx of the thumb

Question 56

What innervates the extensor pollicis brevis?

Answer 56

deep branch of the radial n.

Question 57

What are the actions of the extensor pollicis brevis?

Answer 57

-extends proximal phalanx at thumb at the MCP joint -extends CMC joint

Question 58

When can you see the anatomical snuff box?

Answer 58

when thumb is abducted

Question 59

What is the medial boundary of the anatomical snuffbox? test q

Answer 59

extensor pollicis brevis

Question 60

What is the lateral boundary of the anatomical snuffbox? test q

Answer 60

extensor pollicis longus and abductor pollicis longus

Question 61

What is the floor of the anatomical snuffbox?

Answer 61

scaphoid and trapezium

Question 62

What artery is within the anatomical snuffbox?

Answer 62

radial a.