muscles of the forearm and hand

Question 1

forearm muscles that act primarily at the elbow

Answer 1

• brachialis

- brachioradialis

Question 2

brachialis – origin

Answer 2

distal half of anterior surface of humerus

Question 3

brachialis – insertion

Answer 3

tuberosity + coronoid process of ulna (where biceps brachii inserts)

Question 4

brachialis – action

Answer 4

flex the elbow (works w/ the biceps brachii)

Question 5

brachialis – nerve

Answer 5

musculocutaneous

Question 6

brachioradialis – origin

Answer 6

lateral supracondylar ridge of humerus

same as origin of extensor carpi radialis longus

Question 7

brachioradialis – insertion

Answer 7

styloid process of radius

Question 8

brachioradialis – action

Answer 8

flex the elbow (diff. leverage than biceps brachii + brachialis b/c of diff. origin + insert)

Question 9

_____ is the only muscle that runs length of forearm but does NOT cross the wrist joints.

Answer 9

brachioradialis

Question 10

muscles that move the wrist and/or fingers

Answer 10

carpi, digitorum, or palmaris muscles subdivided into 4 smaller groups:

• extensors of wrist + fingers
• flexors of wrist + fingers
• adductors of wrist
• abductors of wrist

Question 11

extensors of the wrist + fingers (4)

Answer 11

• extensor carpi radialis longus
• extensor carpi radialis brevis
• extensor carpi ulnaris
• extensor digitorum

Question 12

extensors VS. flexors of wrist + fingers

Answer 12

• both extensors + flexors are located b/w brachioradialis + shaft of ulna
• however, extensors are locatedalong forearm’s posterior/lateral surface
• flexors are located along forearm’s anterior/medial surface
• as a group, extensors are smaller + more sinewy than forearm flexors

Question 13

3 extensors of wrist + fingers that originate at lateral epicondyle of humerus

Answer 13

• extensor carpi radialis brevis
• extensor carpi ulnaris
• extensor digitorum

(includes all extensors EXCEPT extensor carpi radialis longus, which originates at lateral SUPRAcondylar ridge of humerus)

Question 14

extensor carpi radialis longus + brevis – origin

Answer 14

• lateral supracondylar ridge of humerus (longus) (same as brachioradialis origin)
• lateral epicondyle of humerus (brevis)

(longus attaches higher up on the humerus; therefore longer)

Question 15

extensor carpi radialis longus + brevis – insertion

Answer 15

• base of 2nd metacarpal (longus)

- base of 3rd metacarpal (brevis)

Question 16

extensor carpi radialis longus + brevis – actions

Answer 16

• extend wrist

- abduct wrist (b/c it inserts at base of 2nd + 3rd metacarpal)

Question 17

extensor carpi ulnaris – origin

Answer 17

lateral epicondyle of humerus

Question 18

extensor carpi ulnaris – insertion

Answer 18

base of 5th metacarpal

“pinky” finger or ulnar side

Question 19

extensor carpi ulnaris – actions

Answer 19

• extend wrist

- adduct wrist (b/c it inserts at base of 5th metacarpal)

Question 20

extensor digitorum – origin

Answer 20

lateral epicondyle of humerus

Question 21

extensor digitorum – insertion

Answer 21

bases of middle + distal phalanges of fingers 2 to 5

“digitorum” fingers

Question 22

extensor digitorum – actions

Answer 22

• extend fingers 2 to 5
• extend wrist

(poly-articulating joint that affects 4 joints: dips, pips, wrist + elbow)

Question 23

extensor indicis – origin

Answer 23

posterior surface of distal shaft of ulna

Question 24

extensor indicis – insertion

Answer 24

attaches to 2 tendons:

• extensor digitorum tendon at the level of the 2nd metacarpal
• extensor indicis tendon

Question 25

extensor indicis -- actions

Answer 25

- extend index finger (at the metacarpophalangeal joint) - adduct index finger (brings it closer to middle finger) - assist to extend the wrist

Question 26

flexors of the wrist + fingers (5)

Answer 26

- flexor carpi radialis - palmaris longus (sometimes absent) - flexor carpi ulnaris - flexor digitorum superficialis - flexor digitorum profundus

Question 27

4 flexors of wrist + fingers that originate at medial epicondyle of humerus

Answer 27

- flexor carpi radialis - palmaris longus - flexor carpi ulnaris - flexor digitorum superficialis (all flexors EXCEPT flexor digitorum profundus, which originates at proximal ulna)

Question 28

flexor carpi radialis -- origin

Answer 28

medial epicondyle of humerus

Question 29

flexor carpi radialis -- insertion

Answer 29

bases of 2nd + 3rd metacarpals

Question 30

flexor carpi radialis -- actions

Answer 30

- flex wrist | - abduct wrist (b/c inserts at 2nd + 3rd metacarpals

Question 31

flexor carpi radialis -- nerve

Answer 31

median nerve

Question 32

flexor carpi ulnaris -- origin

Answer 32

- medial epicondyle of humerus (humeral head) | - posterior surface of proximal ulna (ulnar head)

Question 33

flexor carpi ulnaris -- insertion

Answer 33

- pisiform - hook of hamate - base of 5th metacarpal

Question 34

flexor carpi ulnaris -- actions

Answer 34

- flex wrist | - adduct wrist (b/c insertion points are all at medial wrist)

Question 35

flexor carpi ulnaris -- nerve

Answer 35

ulnar

Question 36

flexor digitorum superficialis -- origin

Answer 36

- medial epicondyle of humerus - ulnar collateral ligament - coronoid process of ulna - iinterosseous membrane - proximal shaft of radius

Question 37

flexor digitorum superficialis -- insertion

Answer 37

sides of middle phalanges of fingers 2 to 5 (tendon is forked)

Question 38

flexor digitorum superficialis -- actions

Answer 38

- flex fingers 2 to 5 (metacarpophalangeal + proximal interphalangeal joints) - flex wrist

Question 39

flexor digitorum superficialis -- nerve

Answer 39

median nerve

Question 40

flexor digitorum profundus -- origin

Answer 40

anterior + medial surfaces of proximal ulna

Question 41

flexor digitorum profundus -- insertion

Answer 41

bases of distal phalanges of fingers 2 to 5

Question 42

flexor digitorum profundus -- action

Answer 42

flex fingers 2 to 5 (metacarpophalangeal + distal interphalangeal joints)

Question 43

flexor digitorum profundus -- nerve

Answer 43

median + ulnar nerves

Question 44

all fingers abduct + adduct around the ____ finger.

Answer 44

middle

Question 45

lateral collateral ligament (LCL)

Answer 45

- prevents lateral deviation of elbow | - aka radial collateral ligament

Question 46

medial collateral ligament (MCL)

Answer 46

- prevents medial deviation of elbow - aka ulnar collateral ligament - a natural "cubitus valgus" curve allows a "carrying angle" (opposite would be "cubitus varus" or "gunstock deformity")

Question 47

interosseous membrane

Answer 47

- fibrous sheet that connects radius + ulna (main part of radio-ulnar syndesmosis, a fibrous joint b/w radius + ulna) - site of attachment for muscles of the forearm - transfers forces from the radius, to the ulna, to the humerus - as the forearm moves from pronation to supination the Interosseous membrane fibres change from a relaxed state, then become tense in the neutral position and then once again become relaxed as the forearm enters supination