Muscles of the Posterior Compartment of the Arm

Question 0

Insertion of Brachioradialis

Answer 0

Lateral Surface of distal end of radius proximal to styloid process

Question 1

Origin of Brachioradialis

Answer 1

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

Question 2

Innervation of Brachioradialis

Answer 2

Radial Nerve (C5,C6,C7)

Question 3

Action of Brachioradialis

Answer 3

Relatively Weak Flexion of the Elbow, maximal when the forearm is in midpronated position

Question 4

Origin of Extensor Carpi Radialis Longus (ECRL)

Answer 4

Lateral Supra-Epicondylar Ridge of the humerus

Question 5

Insertion of the Extensor Carpi Radialis Longus (ECRL)

Answer 5

Dorsal Aspect of Base of 2nd Metacarpal

Question 6

Innervation of Extensor Carpi Radialis Longus (ECRL)

Answer 6

Radial Nerve (C6, C7)

Question 7

Action of Extensor Carpi Radialis Longus (ECRL

Answer 7

Extend and ABduct wrist joint

Question 8

Origin of Extensor Carpi Radialis Brevis (ECRB)

Answer 8

Lateral Epicondyle of the Humerus

Question 9

Insertion of Extensor Carpi Radialis Brevis (ECRB)

Answer 9

Dorsal Aspect of Base of 3rd Metacarpal

Question 10

Innervation of Extensor Carpi Radialis Brevis (ECRB)

Answer 10

Deep Branch of Radial Nerve (C7, C8)

Question 11

Action of Extensor Carpi Radialis Brevis (ECRB)

Answer 11

Extend and ABduct the Wrist Joint; Extensor Carpi Radialis Brevis active during clenching of fist

Question 12

Origin of Extensor Digitorum

Answer 12

Lateral Epicondyle of the Humerus

Question 13

Insertion of Extensor Digitorum

Answer 13

Extensor Expansion of Medial Four Fingers

Question 14

Innervation of Extensor Digitorum

Answer 14

Posterior Interosseous Nerve (C7,C8), Continuation of Deep Branch of Radial Nerve

Question 15

Action of Extensor Digitorum

Answer 15

1) Extend Wrist Joint

2) Extend Medial Four Fingers primarily at metapophalangeal joints, secondarily at interphalangeal joints

Question 16

Origin of Extensor Digiti Minimi

Answer 16

Lateral Epicondyle of Humerus

Question 17

Insertion of Extensor Digiti Minimi

Answer 17

Extensor Expansion of 5th Finger

Question 18

Innervation of Extensor Digiti Minimi

Answer 18

Posterior Interosseous Nerve (C7,C8) , continuous of deep branch of radial nerve

Question 19

Action of Extensor Digiti Minimi

Answer 19

1) Extends wrist joint

2) Extends 5th finger primarily at the metacarpophalangeal joint, secondarily at the interphalangeal joint

Question 20

Origin of Extensor Carpi Ulnaris (ECU)

Answer 20

1) Lateral Epicondyle of the Humerus

2) Posterior Border of Ulna via a shared aponeurosis

Question 21

Insertion of Extensor Carpi Ulnaris

Answer 21

Dorsal Aspect of Base of 5th Metacarpal

Question 22

Innervation of Extensor Carpi Ulnaris (ECU)

Answer 22

Posterior Interosseous Nerve (C7,C8), continuation of deep branch of radial nerve

Question 23

Action of Extensor Carpi Ulnaris (ECU)

Answer 23

1) Extend and ADDuct the wrist joint

2) Extensor Carpi Ulnaris also active during fist clenching

Question 24

Superficial Layer of Muscles of Posterior Compartment of Forearm

Answer 24

``` Brachioradialis Extensor Carpi Radialis Longus Extensor Carpi Raidalis Brevis Extensor Digitorum Extensor Digiti Minimi Extensor Carpi Ulnaris ```

Question 25

Which Muscle is in the Deep Layer of the Posterior Compartment of the Forearm

Answer 25

Supinator

Question 26

Origin of the Supinator

Answer 26

1) Lateral Epicondyle of the Humerus 2) Radial Collateral and Anular Ligament 3) Supinator Fossa 4) Crest of Ulna

Question 27

Insertion of Supinator

Answer 27

Lateral, Posterior, and Anterior Proximal 1/3 of the Radius

Question 28

Innervation of Supinator

Answer 28

Deep Branch of Radial Nerve (C7,C8)

Question 29

Action of Supinator

Answer 29

1) Supinates the Forearm 2) Rotate the Radius to turn palm anteriorly or posteriorly (if Elbow is flexed)

Question 30

Origin of Abductor Pollicis Longus

Answer 30

Posterior Surface of Proximal Halves of Ulna, Radius, and Interosseous Membrane

Question 31

Insertion of the Abductor Pollicis Longus

Answer 31

Base of the 1st Metacarpal

Question 32

Innervation of Abductor Pollicis Longus

Answer 32

Posterior Interosseus Nerve (C7, C8), Continuation of Deep Branch of Radial Nerve

Question 33

Action of Abductor Pollicis Longus

Answer 33

1) Extends Wrist Joint 2) Abducts the thumb and extends it at carpometacarpal joint

Question 34

What muscles make the "outcropping" of deep layer of posterior compartment of arm?

Answer 34

1) Abductor Pollicis Longus 2) Extensor Pollicis Longus 3) Extensor Pollicis Brevis 4) Extensor Indicis

Question 35

Origin of the Extensor Pollicis Longus

Answer 35

Posterior Surface of Middle Third of Ulna and Interosseous Membrane

Question 36

Insertion of the Extensor Pollicis Longus

Answer 36

Dorsal Aspect of the Base of the Distal Phalanx of the Thumb

Question 37

Innervation of Extensor Pollicis Longus

Answer 37

Posterior Interosseous Nerve (C7,C8), Continuation of deep branch of radial nerve

Question 38

Action of Extensor Pollicis Longus

Answer 38

1) Extend wrist joint | 2) Extend the distal phalanx at the interphalangeal joint, extend metacarpophalangeal and carpometacarpal joints

Question 39

Origin of Extensor Pollicis Brevis

Answer 39

Posterior Surface of Distal Third of Radius and Interosseous Membrae

Question 40

Insertion of Extensor Pollicis Brevis

Answer 40

Dorsal Aspect of Base of Proximal Phalanx of Thumb

Question 41

Innervation of Extensor Pollicis Brevis

Answer 41

Posterior Interosseous Nerve (C7,C8), Continuation of Deep Branch of Radial Nerve

Question 42

Action of Extensor Pollicis Brevis

Answer 42

1) Extends Wrist Joint | 2) Extends Proximal Phalanx at metacarpophalangeal joint; extends carpometacarpal joint

Question 43

Origin of Extensor Indicis

Answer 43

Posterior Surface of Distal Third of Ulna and Interosseous Membrane

Question 44

Insertion of Extensor Indicis

Answer 44

Extensor Expansion of 2nd Finger (Index Finger)

Question 45

Innervation of Extensor Indicis

Answer 45

Posterior Interosseous Nerve (C7, C8), Continuation of Deep Branch of Radial Nerve

Question 46

Action of Extensor Indicis

Answer 46

1) Extend wrist joint | 2) Extend 2nd Finger (enabling its independent extension); helps extend hand at wrist