Muscles of the Upper Extremity: Extensor-Supinator Compartment of the Foremarm

Question 1

Brachioradialis Proximal Attachment

Answer 1

Proximal 2/3 of the lateral supracondylar ridge of the humerus

Question 2

Brachioradialis Distal Attachment

Answer 2

Styloid process of the radius

Question 3

Brachioradialis Innervation

Answer 3

Radial n. [C5,*C6,C7]

Question 4

Brachioradialis Action

Answer 4

Flexes the elbow
Assists with:
-Forearm pronation and supination against resitance

Question 5

Extensor Carpi Radialis Longus Proximal Attachment

Answer 5

Distal third of lateral supracondylar ridge of humerus

Question 6

Extensor Carpi Radialis Longus Distal Attachment

Answer 6

Bases of metacarpal II

Question 7

Extensor Carpi Radialis Longus Innervation

Answer 7

Radial n. [*C6,C7]

Question 8

Extensor Carpi Radialis Longus Action

Answer 8

Extends the wrist
Abducts the wrist
Assists with:
-Elbow flexion

Question 9

Extensor Carpi Radialis Brevis Proximal Attachment

Answer 9

Common extensor tendon at the lateral epicondyle of the humerus

Question 10

Extensor Carpi Radialis Brevis Distal Attachment

Answer 10

Base of metacarpal III

Question 11

Extensor Carpi Radialis Brevis Innervation

Answer 11

Radial n. [*C6,C7]

Question 12

Extensor Carpi Radialis Brevis Action

Answer 12

Extends the wrist
Abducts the wrist
Assists with:
-Elbow flexion

Question 13

Extensor Digitorum Proximal Attachment

Answer 13

Common extensor tendon at the lateral epicondyle of the humerus

Question 14

Extensor Digitorum Distal Attachment

Answer 14

Dorsal surfaces of digits II-V via extensor hood (by central slip to the base of the middle phalanx, and by lateral bands to the base of the distal phalanx)

Question 15

Extensor Digitorum Innervation

Answer 15

Posterior Interosseous n. (Radial) [*C7,C8]

Question 16

Extensor Digitorum Action

Answer 16

Extends the MCP, PIP, & DIP joints of digits 2-5
Assists with:
-Wrist extension

Question 17

Extensor Carpi Ulnaris Proximal Attachment

Answer 17

Common extensor tendon at the lateral epicondyle of humerus, and posterior border of ulna

Question 18

Extensor Carpi Ulnaris Distal Attachment

Answer 18

Metacarpal V

Question 19

Extensor Carpi Ulnaris Innervation

Answer 19

Posterior Interosseous n. (Radial) [*C7,C8]

Question 20

Extensor Carpi Ulnaris Action

Answer 20

Extends the wrist

Adducts the wrist

Question 21

Extensor Digiti Minimi Proximal Attachment

Answer 21

Common extensor tendon at the lateral epicondyle of the humerus

Question 22

Extensor Digiti Minimi Distal Attachment

Answer 22

Extensor hood of digit V with ED tendon

Question 23

Extensor Digiti Minimi Innervation

Answer 23

Posterior Interosseous n. (Radial) [*C7,C8]

Question 24

Extensor Digiti Minimi Action

Answer 24

Extends MCP, PIP, & DIP joints of the little finger

Question 25

Supinator Proximal Attachment

Answer 25

Lateral epicondyle of the humerus radial collateral ligament, annular ligament, and supinator crest of the ulna

Question 26

Supinator Distal Attachment

Answer 26

Lateral surface of the proximal third of the radius

Question 27

Supinator Innervation

Answer 27

Radial n. [*C6,C7]

Question 28

Supinator Action

Answer 28

Supinates the forearm

Question 29

Abductor Pollicis Longus Proximal Attachment

Answer 29

Midway along the posterior surface of the radius and ulna and interosseous membrane

Question 30

Abductor Pollicis Longus Distal Attachment

Answer 30

Base of metacarpal I

Question 31

Abductor Pollicis Longus Innervation

Answer 31

Posterior Interosseous n. (Radial) [*C7,C8]

Question 32

Abductor Pollicis Longus Action

Answer 32

``` Abducts CMC joint of the thumb Extends CMC joint of the thumb Assists with: -Wrist abduction -Wrist flexion ```

Question 33

Extensor Pollicis Brevis Proximal Attachment

Answer 33

Posterior surface of the distal radius

Question 34

Extensor Pollicis Brevis Distal Attachment

Answer 34

Base of the proximal phalanx of the thumb

Question 35

Extensor Pollicis Brevis Innervation

Answer 35

Posterior Interosseous n. (Radial) [*C7,C8]

Question 36

Extensor Pollicis Brevis Action

Answer 36

Extends CMC & MCP joint of the thumb Abducts CMS joint of the thumb Assists with: -Wrist abduction

Question 37

Extensor Pollicis Longus Proximal Attachment

Answer 37

Middle of the posterior surface of the ulna

Question 38

Extensor Pollicis Longus Distal Attachment

Answer 38

Base of the distal phalanx of the thumb

Question 39

Extensor Pollicis Longus Innervation

Answer 39

Posterior Interosseous n. (Radial) [*C7,C8]

Question 40

Extensor Pollicis Longus Action

Answer 40

Extends CMC, MCP, & IP joints of the thumb Assists with: -Wrist abduction

Question 41

Extensor Indicis Proximal Attachment

Answer 41

Posterior surface of the ulna, distal to the origin of extensor pollicis longus

Question 42

Extensor Indicis Distal Attachment

Answer 42

Extensor hood of digit I with ED tendon

Question 43

Extensor Indicis Innervation

Answer 43

Posterior Interosseous n. (Radial) [*C7,C8]

Question 44

Extensor Indicis Action

Answer 44

Extends MCP, PIP, & DIP joints of the index finger Adducts MCP joint of the index finger Assists with: -Wrist extension