Posterior Forearm Muscles

Question 1

Brachioradialis Origin

Answer 1

Proximal portion of lateral supracondylar ridge of humerus and adjacent lateral intermuscular septum

Question 2

Brachioradialis Insertion

Answer 2

Lateral side, distal end of the radius, proximal to the radial styloid process

Question 3

Brachioradialis Innervation

Answer 3

Radial nerve (C5/C6)

Question 4

Brachioradialis Action

Answer 4

Elbow flexion, with forearm in mid-supination / Mid-pronation

Question 5

Extensor Carpi Radialis Longus Origin

Answer 5

Distal portion of supracondular ridge of humerus bone and lateral intermuscular septum

Question 6

Extensor Carpi Radialis Longus Insterion

Answer 6

Doral surface, base of MC #2

Question 7

Extensor Carpi Radialis Longus Innervation

Answer 7

Radial Nerve (C6/C7)

Question 8

Extensor Carpi Radialis Longus Action

Answer 8

Wrist extension and radial deviation

Question 9

Extensor Carpi Radialis Brevis Origin

Answer 9

Lateral Epicondyle of humerus through Common Extensor Tendon (CET); Lateral/radial collateral ligament of elbow; and adjacent intermuscular septum

Question 10

Extensor Carpi Radialis Brevis Insertion

Answer 10

Dorsal surface, base of MC #2 and #3

Question 11

Extensor Carpi Radialis Brevis Innervation

Answer 11

Deep Radial Nerve (C7/C8)

Question 12

Extensor Carpi Radialis Brevis Action

Answer 12

Wrist extension, radial deviation

Question 13

Extensor Digitorum Origin

Answer 13

Lateral epicondyle through common extensor tendon (CET) and adjacent intermuscular septum

Question 14

Extensor Digitorum Insertion

Answer 14

Dorsal Digital Expansion (DDE) of fingers 2-5 (essentially inserting on the dorsal aspect of bases of middle and distal phalanges)

Question 15

Extensor Digitorum Innervation

Answer 15

Posterior Interosseous Nerve (C7/C8)

Question 16

Extensor Digitorum Action

Answer 16

Extension of fingers 2-5, wrist extension

Question 17

Extensor Digiti Minimi Origin

Answer 17

Lateral epicondyle of humerus by common extensor tendon (CET) and adjacent intermuscular septum

Question 18

Extensor Digiti Minimi Insertion

Answer 18

Dorsal Digital Expansion (DDE) of little finger-medial side

Question 19

Extensor Digiti Minimi Innervation

Answer 19

Posterior Interosseous Nerve (C7/C8)

Question 20

Extensor Digiti Minimi Action

Answer 20

Extension of 5th finger, assists with wrist extension

Question 21

Extensor Carpi Ulnaris Origin

Answer 21

Humeral Head: Lateral Epicondyle of the humerus via Common Extensor Tendon (CET)

Ulnar Head: Posterior border of ulna by aponeurosis

Question 22

Extensor Carpi Ulnaris Insertion

Answer 22

Base of MC #5, Medial side

Question 23

Extensor Carpi Ulnaris Innervation

Answer 23

Posterior interosseous Nerve (C7/C8)

Question 24

Extensor Carpi Ulnaris Action

Answer 24

Wrist extension, Ulnar deviation

Question 25

Aconeus Origin

Answer 25

Posterior surface of the lateral epicondyle of the humerus

Question 26

Aconeus Insertion

Answer 26

Lateral side of the olecranon process and upper posterior surface of ulna

Question 27

Aconeus Innervation

Answer 27

Radial nerve (C6/C7/C8)

Question 28

Aconeus Action

Answer 28

Abduction of ulna during pronation of forearm; assists with forearm extention

Question 29

Supinator Origin

Answer 29

Humeral Head: Lateral epicondyle of the humerus bone by Common Extensor Tendon; Radial collateral ligament and annular ligament of radius Ulnar head: Supinator crest of the ulna

Question 30

Supinator Insertion

Answer 30

Lateral surface; Proximal 1/3 radius

Question 31

Supinator Innervation

Answer 31

Posterior Interosseous Nerve (C6/7)

Question 32

Supinator Action

Answer 32

forearm supination

Question 33

ABductor Pollicis Longus Origin

Answer 33

Posterior surface of ulna and radius and interosseous membrane (upper portion of ulna and middle 1/3 of radius)

Question 34

ABductor Pollicis Longus Insertion

Answer 34

Base of MC #1, lateral side

Question 35

ABductor Pollicis Longus Innervation

Answer 35

Posterior Interosseous Nerve - PIN (C7/C8)

Question 36

ABductor Pollicis Longus Action

Answer 36

Abduction of thumb at CM joint; Assists with thumb extension and radial deviation

Question 37

Extensor Pollicis Brevis Origin

Answer 37

Posterior surface of radius (below Abductor pollicis longus) and interosseous membrane.

Question 38

Extensor Pollicis Brevis Insertion

Answer 38

Base of proximal phalanx of thumb, dorsal surface

Question 39

Extensor Pollicis Brevis Innervation

Answer 39

Posterior Interosseous Nerve ( C7/C8)

Question 40

Extensor Pollicis Brevis Action

Answer 40

Extension of the thumb (at MP and CM joints) assists with wrist radial deviation.

Question 41

Extensor Pollicis Longus Origin

Answer 41

Posterior surface, middle 1/3 of ulna and interosseous membrane

Question 42

Extensor Pollicis Longus Insertion

Answer 42

Base of the distal phalanx of the thumb, dorsal side

Question 43

Extensor Pollicis Longus Innervation

Answer 43

Posterior Interosseous Nerve, (C7/C8)

Question 44

Extensor Pollicis Longus Action

Answer 44

Thumb extension at Ip, MP, and CM joints, rotates thumb laterally so pad is out.

Question 45

Extensor Indicis Origin

Answer 45

Posterior surface of the ulna (distal to the EPL) and interosseous membrane

Question 46

Extensor Indicis Insertion

Answer 46

Dorsal digital expansion. (DDE) of the index finger, medial side

Question 47

Extensor Indicis Innervation

Answer 47

Posterior interosseous nerve (C7/C8)

Question 48

Extensor Indicis Action

Answer 48

Extension of the index finger

Question 49

Superficial Posterior Forearm Muscles

Answer 49

1. Brachioradialis 2. Extensor Carpi Radialis Longus 3. Extensor Carpi Radialis Brevis 4. Extensor Digitorum 5. Extensor Digiti Minimi 6. Extensor Carpi Ulnaris 7. Anconeous

Question 50

Deep Posterior Forearm Muscles

Answer 50

1. Abductor pollicis Longus 2. Extensor pollicis Brevis 3. Extensor Pollicis Longus 4. Supinator muscle 5. Extensor indicis