Muscles of the Posterior Compartment of the Forearm

Question 1

What is the general function of the muscles of the posterior compartment of the forearm

Answer 1

Extension at the wrist and fingers

Question 2

Which nerve innervates the muscles of the posterior compartment of the forearm

Answer 2

Radial nerve

Question 3

What are the superficial muscles of the posterior forearm

Answer 3

Extensor carpi radialis brevis
Extensor carpi radialis longus
Extensor digitorum
Extensor carpi ulnaris 
Extensor digiti minimi
Brachioradialis
Anconeus

Question 4

Which superficial muscles of the posterior forearm share a common tendinous origin

Answer 4

Extensor carpi radialis brevis
Extensor digitorum
Extensor carpi ulnaris
Extensor digiti minimi
(At lateral epicondyle)

Question 5

In the distal forearm, where does the radial artery and nerve lie

Answer 5

Between brachioradialis and deep flexor muscles

Question 6

Where does brachioradialis originate

Answer 6

Proximal aspect of the lateral supracondylar ridge of humerus

Question 7

Where does brachioradialis insert

Answer 7

Distal end of the radius, just before the radial styloid process

Question 8

What is the function of brachioradialis

Answer 8

Flexion at the elbow

Question 9

What nerve innervates brachioradialis

Answer 9

Radial nerve

Question 10

Where does extensor carpi radialis longus originate

Answer 10

Supracondylar ridge

Question 11

Where does the extensor carpi radialis brevis originate

Answer 11

Lateral epicondyle

Question 12

Where do extensor carpi radialis longus and brevis insert

Answer 12

Metacarpal bones II and III

Question 13

What is the action of extensor carpi radialis

Answer 13

Extends and abducts the wrist

Question 14

Which nerve innervates extenor carpi radialis

Answer 14

Radial nerve

Question 15

Where does extensor digitorum originate

Answer 15

Lateral epicondyle

Question 16

Where does extensor digitorum insert

Answer 16

Tendon splits into 4 and inserts into the extensor hood of each finger

Question 17

What is the action of extensor digitorum

Answer 17

Main extensor of the four fingers at MCP and IP joints

Question 18

Which nerve innervates extensor digitorum

Answer 18

Radial nerve (deep branch)

Question 19

Where does extensor digiti minimi lie

Answer 19

Medially to extensor digitorum

Question 20

Where does extensor digiti minimi originate

Answer 20

Lateral epicondyle of the humerus

Question 21

Where does extensor digiti minimi insert

Answer 21

Extensor hood of the little finger

Question 22

What is the action of extensor digiti minimi

Answer 22

Extends the little finger

Contributes to extension at the wrist

Question 23

Which nerve innervates extensor digiti minimi

Answer 23

Radial nerve (deep branch)

Question 24

Where is extensor carpi ulnaris located

Answer 24

Medial aspect of the posterior forearm

Question 25

Where does extensor carpi ulnaris originate

Answer 25

Lateral epicondyle of the humerus

Question 26

Where does extensor carpi ulnaris insert

Answer 26

Base of metacarpal V

Question 27

What is the action of extensor carpi ulnaris

Answer 27

Extension and adduction of the wrist

Question 28

Which nerve innervates extensor carpi ulnaris

Answer 28

Radial nerve (deep branch)

Question 29

Where does anconeus lie

Answer 29

Medially and superiorly in the extensor compartment of the forearm Blended with the fibres of triceps brachii

Question 30

Where does anconeus originate

Answer 30

Lateral epicondyle

Question 31

Where does anconeus insert

Answer 31

Posterior and lateral part of olecranon

Question 32

What is the action of anconeus

Answer 32

Extends and stabilises elbow joint | Abducts ulna during pronation of forearm

Question 33

Which nerve innervates anconeus

Answer 33

Radial nerve

Question 34

What is lateral epicondylitis

Answer 34

Inflammation of the periosteum of the lateral epicondyle - caused by repeated use of superficial extensor muscles

Question 35

What are the deep muscles of the posterior forearm

Answer 35

``` Supinator Abductor pollicis longus Extensor pollicis brevis Extensor pollicis longus Extensor indicis ```

Question 36

Where does supinator lie

Answer 36

Floor of the cubital fossa

Question 37

What passes between the two heads of supinator

Answer 37

Deep branch of the radial nerve

Question 38

Where does supinator originate

Answer 38

Two heads:- Lateral epicondyle of the humerus Posterior surface of the ulna

Question 39

Where does supinator insert

Answer 39

Posterior surface of the radius

Question 40

What is action of supinator

Answer 40

Supinates forearm

Question 41

Which nerve innervates supinator

Answer 41

Radial nerve (deep branch)

Question 42

Where is abductor pollicis longus

Answer 42

Immediately distal to supinator

Question 43

Where does abductor pollicis longus originate

Answer 43

Interosseous membrane | Adjacent posterior surfaces of the radius and ulna

Question 44

Where does abductor pollicis longus insert

Answer 44

Lateral side of the base of metacarpal I

Question 45

What is the action of abductor pollicis longus

Answer 45

Abducts the thumb

Question 46

Which nerve innervates abductor pollicis longus

Answer 46

Radial nerve (posterior interosseous branch)

Question 47

Where does extensor pollicis brevis lie

Answer 47

Medially and deep to abductor pollicis longus

Question 48

Where does extensor pollicis brevis originate

Answer 48

Posterior surface of the radius and interosseous membrane

Question 49

Where does extensor pollicis brevis insert

Answer 49

Base of the proximal phalanx of the thumb

Question 50

What is the action of extensor pollicis brevis

Answer 50

Extends thumb at MCPJ and carpometacarpal joints

Question 51

Which nerve innervates extensor pollicis brevis

Answer 51

Posterior interosseous branch of the radial nerve

Question 52

Where does extensor pollicis longus originate

Answer 52

Posterior surface of the ulna and interosseous membrane

Question 53

Where does extensor pollicis longus insert

Answer 53

Distal phalanx of the thumb

Question 54

What is the action of extensor pollicis longus

Answer 54

Extends all joints of the thumb

Question 55

Which nerve innervates extensor pollicis longus

Answer 55

Radial nerve

Question 56

Where does extensor indicis proprius originate

Answer 56

Posterior surface of the ulna and interosseous membrane (distal to extensor pollicis longus)

Question 57

Where does extensor indicis proprius insert

Answer 57

Extensor hood of the index finger

Question 58

What is the action of extensor indicis proprius

Answer 58

Extends index finger

Question 59

Which nerve innervates extensor indicis proprius

Answer 59

Posterior interosseous branch of the radial nerve

Question 60

What is a sign of radial nerve damage

Answer 60

Wrist drop

Question 61

Where are the common sites of radial nerve damage

Answer 61

Axilla | Radial groove of the humerus