MSK 11 - Forearm and extensor aspect

Question 1

how many superficial extensor muscles are there in the forearm

Answer 1

7

Question 2

what are the 7 superficial extensor muscles in the forearm

Answer 2

brachioradialis
anconeus
extensor carpi radialis longus
extensor carpi radialis brevis
extensor carpi ulnaris
extensor digiti minimi
extensor digitorum

Question 3

what is the one muscle of the extensor superficial muscles of the forearm that is on the anterior forearm instead of being on the posterior side of the forearm

Answer 3

brachioradialis

Question 4

what is the origin and insertion of brachioradialis

Answer 4

origin = supracondylar ridge

insertion = base of radial styloid process

Question 5

what is the role and action of brachioradialis

Answer 5

the one muscle in extensor compartment that flexes the forearm

shunt muscle for elbow

Question 6

what structure runs medially down the medial side of the brachioradialis

Answer 6

radial artery and nerve

Question 7

what is the origin and insertion of anconeus

Answer 7

origin = supracondylar ridge

insertion = neck of ulna

Question 8

what is the origin and insertion of extensor carpi radialis longus

Answer 8

origin = supracondylar ridge

insertion = base of 2nd metacarpal

Question 9

what is the origin and insertion of extensor carpi radialis brevis

Answer 9

origin = common extensor tendon

insertion = base of 3rd metacarpal

Question 10

what is the origin and insertion of extensor carpi ulnaris

Answer 10

origin = common extensor tendon

insertion = base of 5th metacarpal

Question 11

what is the origin and insertion of extensor digiti minimi

Answer 11

origin = common extensor tendon

insertion = base of 5 proximal phalanges

Question 12

what is the origin and insertion of extensor digitorum

Answer 12

origin = common extensor tendon

insertion = dorsal digital expansion hood

Question 13

what connects the extensor digitorum tendons at the metacarpal level

Answer 13

intertendinous bands

Question 14

what is the action of anconeus

Answer 14

extension of elbow

Question 15

what are the two tendons that make up the anatomical snuff box borders

Answer 15

extensor pollicis longus (medially) and extensor pollicis brevis (laterally)

Question 16

what do the carpi muscles do what is its role

Answer 16

stabilize the wrist

Question 17

what is the clinical sign of radial nerve damage

what movement does this affect and why does this occur

Answer 17

wrist drop

radial nerve damage affects flexor efficiency

when using powerful grip wrist is slightly extended so flexor muscles are at appropriate length and gives strength - this is lacking in radial nerve damage

Question 18

what is the movement generated when the FCU and FCR are fired together

Answer 18

only flexion

Question 19

what is the movement generated when the FCU and ECU are fired together

Answer 19

adduction only

Question 20

what is the movement generated when the ECU and ECRL/ECRB are fired together

Answer 20

extension only

Question 21

what is the movement generated when the ECRL/ECRB and FCR are fired together

Answer 21

only abduction

Question 22

what is the movement generated when only the FCU is fired

Answer 22

flexion and adduction

Question 23

what is the movement generated when only the FCR is fired

Answer 23

flexion and abduction

Question 24

what is the movement generated when only the ECU is fired

Answer 24

adduction and extension

Question 25

what is the movement generated when only the ECRB and ECRL are fired

Answer 25

abduction and extension

Question 26

how many deep extensor muscles are there in the forearm

Answer 26

6 - technically 5

Question 27

what are the 6 deep extensor muscles in the forearm

Answer 27

supinator deep head supinator superficial head extensor pollicis longus extensor pollicis brevis abductor pollicis longus extensor indicis

Question 28

what is the origin and insertion of extensor pollicis longus

Answer 28

origin = back of radius and interosseous membrane insertion = base of distal phalanx of thumb

Question 29

what is the origin and insertion of extensor indicis

Answer 29

origin = back of radius and interosseous membrane insertion = dorsal digital expansion hood

Question 30

what is the origin and insertion of abductor pollicis longus

Answer 30

origin = back of radius and interosseous membrane insertion = base of 1st metacarpal

Question 31

what is the origin and insertion of extensor pollicis brevis

Answer 31

origin = back of the interosseous membrane insertion = base of proximal phalanx of thumb

Question 32

does the extensor indicis interact with the other extensor digitorum tendons at all what does this mean in terms of movement

Answer 32

doesnt interact at all can extend index finger with the 3rd and 4th flexed but cant do this the other way around

Question 33

what is the origin and insertion of supinator (deep head)

Answer 33

origin = proximal radius insertion = lateral epicondyle

Question 34

what is the origin and insertion of supinator (superficial head)

Answer 34

origin = proximal radius insertion = crest beside radial notch

Question 35

what structure runs between the supinator muscle - describe its path

Answer 35

radial nerve runs down the posterior humerus and lateral of elbow between brachioradialis and brachialis then the deep radial nerve branch dives between the heads of the supinator muscle

Question 36

describe the path of the radial nerve in terms of its branching

Answer 36

radial nerve splits into deep and superficial branches at the supinator muscle below the lateral epicondyle the deep branch goes on to become the posterior interosseous nerve the superficial branch continues down the forearm to the wrist

Question 37

what muscles are innervated by the radial nerve itself - 4 muscles

Answer 37

triceps anconeus brachioradialis extensor carpi radialis longus

Question 38

what muscles are innervated by the deep branch of the radial nerve - 2 muscles

Answer 38

extensor carpi radialis brevis supinator

Question 39

what muscles are innervated by the posterior interosseous nerve - 7 muscles

Answer 39

extensor digitorum extensor digiti minimi extensor carpi ulnaris abductor pollicis longus extensor pollicis longus extensor indicis extensor pollicis brevis

Question 40

where does the radial nerve deep branch become the posterior interosseous nerve

Answer 40

between supinator muscle

Question 41

what does the superficial branch of the radial nerve innervate

Answer 41

back of hand - just cutaneous