Posterior Extensor Compartment of the Forearm

Question 1

Layers of the Posterior Compartment?

Answer 1

Superficial

Deep

Question 2

General common origin of extensor muscles?

Answer 2

Lateral Epidcondyle of the Humerus

Question 3

Muscles in the Superficial Compartment

Answer 3

Brachioradialis
Extensor Carpi Radialis Longus
Extensor Carpi Radialis Brevis
Extensor Digitorum
Extensor Carpi Ulnaris
Extensor Digiti Minimi
Anconeus

Question 4

Muscles in the Deep Compartment

Answer 4

Supinator
Extensor Pollicis Longus
Extensor Pollicis Brevis
Abductor Pollicis Longus
Extensor Indicis

Question 5

Function of Brachioradialis

Answer 5

Accessory flexor during mid pronation despite being in the posterior extensor compartment!

Question 6

Origin of Brachioradialis

Answer 6

Lateral Supraepicondylar Ridge

Adjacent Intermuscular Septum

Question 7

Insertion of Brachioradialis

Answer 7

Lateral Distal Radius

Question 8

Innervation of Brachioradialis

Answer 8

Radial Nerve

Question 9

Function of Extensor Carpi Radialis Longus

Answer 9

Extends and abducts the wrist

Question 10

Origin of Extensor Carpi Radialis Longus

Answer 10

Supraepicondylar ridge

Adjacent Intermuscular Septum

Question 11

Insertion of Extensor Carpi Radialis Longus

Answer 11

Base of Metacarpal 2

Question 12

Innervation of Extensor Carpi Radialis Longus

Answer 12

Radial Nerve

Question 13

Function of Extensor Carpi Radialis Brevis

Answer 13

Extends and abducts the wrist

Question 14

Origin of Extensor Carpi Radialis Brevis

Answer 14

Lateral Epicondyle

Adjacent Intermuscular Septum

Question 15

Insertion of Extensor Carpi Radialis Brevis

Answer 15

Base of Metacarpals 2 and 3

Question 16

Innervation of Extensor Carpi Radialis Brevis

Answer 16

Radial Nerve (deep branch)

Question 17

Function of Extensor Digitorum

Answer 17

Extensor of Digits 2-5 (and wrist)

Question 18

Origin of Extensor Digitorum

Answer 18

Lateral Epicondyle

Adjacent Intermuscular Septum and Deep fascia

Question 19

Insertion of Extensor Digitorum

Answer 19

Middle and Distal Phalanges of Digits 2- 5 via Extensor Hoods

Question 20

Innervation of Extensor Digitorum

Answer 20

Posterior Interosseous Nerve

continuation of deep branch of radial nerve

Question 21

Function of Extensor Digiti Minimi

Answer 21

Accessory extension of Digit 5

Question 22

Origin of Extensor Digiti Minimi

Answer 22

Lateral Epicondyle
Adjacent Intermuscular Septum

Inserts with Extensor Digitorum

Question 23

Insertion of Extensor Digiti Minimi

Answer 23

Extensor hood of digit 5

Question 24

Innervation of Extensor Digiti Minimi

Answer 24

Posterior Interosseous Nerve

continuation of deep branch of radial nerve

Question 25

Function of Extensor Carpi Ulnaris

Answer 25

Extension and adduction of the wrist

Question 26

Origin of Extensor Carpi Ulnaris

Answer 26

Lateral Epicondyle | Ulna

Question 27

Insertion of Extensor Carpi Ulnaris

Answer 27

Base of Metacarpal 5 (medial side)

Question 28

Innervation of Extensor Carpi Ulnaris

Answer 28

Radial Nerve (branch to medial head of triceps)

Question 29

Function of Anconeus

Answer 29

Abduction of ulna during pronation | Accessory flexor

Question 30

Origin of Anconeus

Answer 30

Lateral Epicondyle

Question 31

Insertion of Anconeus

Answer 31

Posterior Ulna and Olecranon

Question 32

Innervation of Anconeus

Answer 32

Radial Nerve (branch to medial head of triceps)

Question 33

Function of Supinator

Answer 33

Supination of the arm and hand

Question 34

Origin of Supinator

Answer 34

Lateral Epicondyle and ligaments (superficial head) | Supinator crest of ulna (deep head)

Question 35

Insertion of Supinator

Answer 35

Lateral surface of radius (superior to anterior oblique line)

Question 36

Innervation of Supinator

Answer 36

Deep Branch of Radial Nerve (Posterior Interosseus Nerve

Question 37

Function of Abductor Pollicis Longus

Answer 37

Abduction of Digit 1 | at joint between metacarpal and trapezium

Question 38

Origin of Abductor Pollicis Longus

Answer 38

Posterior Ulna and Radius | Interosseus Membrane

Question 39

Insertion of Abductor Pollicis Longus

Answer 39

Lateral base of Metacarpal 1

Question 40

Innervation of Abductor Pollicis Longus

Answer 40

Posterior Interosseous Nerve | continuation of deep branch of radial nerve

Question 41

Function of Extensor Pollicis Brevis

Answer 41

Extension of Metacarpo-phalangeal and carpometacarpal joints of the Thumb

Question 42

Origin of Extensor Pollicis Brevis

Answer 42

Posterior Radius distal to Abductor PB origin | Interosseus Membrane

Question 43

Insertion of Extensor Pollicis Brevis

Answer 43

Dorsal base of Proximal Phalanx of Digit 1

Question 44

Innervation of Extensor Pollicis Brevis

Answer 44

Posterior Interosseous Nerve | continuation of deep branch of radial nerve

Question 45

Function of Extensor Pollicis Longus

Answer 45

Extension of all thumb joints

Question 46

Origin of Extensor Pollicis Longus

Answer 46

Posterior Ulna | Adjacent Interosseus Membrane

Question 47

Insertion of Extensor Pollicis Longus

Answer 47

Dorsal base of Distal Phalanx of Digit 1

Question 48

Innervation of Extensor Pollicis Longus

Answer 48

Posterior Interosseous Nerve | continuation of deep branch of radial nerve

Question 49

Function of Extensor Indicis

Answer 49

Accessory extensor of the index finger (Digit 2)

Question 50

Origin of Extensor Indicis

Answer 50

Posterior Ulna | Adjacent Interosseus Membrane

Question 51

Insertion of Extensor Indicis

Answer 51

Extensor hood of Digit 2

Question 52

Innervation of Extensor Indicis

Answer 52

Posterior Interosseous Nerve | continuation of deep branch of radial nerve