Muscles of the Back of Forearm : Superficial

Question 1

List the superficial muscles found in the back of the forearm, from lateral to medial(7)

Answer 1

1. Brachio-radialis
2. Extensor Carpi Radialis Longus
3. Extensor Carpi Radialis Brevis
4. Extensor Digitorum
5. Extensor Digiti Minimi
6. Extensor Carpi Ulnaris
7. Anconeus

Question 2

Origin of brachio-radialis

Answer 2

1. From the upper 2/3 of lateral supracondylar ridge of humerus
2. Lateral intermuscular septum of the arm

Question 3

insertion of brachio-radialis

Answer 3

Into lateral surface of lower end of radius just above the styloid process

Question 4

Nerve supply of brachio-radialis

Answer 4

Radial nerve (by a branch arising on the lateral side of the arm)

Question 5

Actions of brachio-radialis

Answer 5

1. Initiates pronation and supination of the forearm
2. Flexion of the forearm in the midprone position (muscle of military salute)

Question 6

Origin of Extensor Carpi Radialis Longus

Answer 6

1. Lower 1/3 of lateral supracondylar ridge of humerus
2. From lateral intermuscular septum of the arm

Question 7

Insertion of Extensor Carpi Radialis Longus

Answer 7

Into the back of the base of the 2nd metacarpal bone

Question 8

Nerve Supply of Extensor Carpi Radialis Longus

Answer 8

Radial nerve (by a branch arising on the lateral side of the arm)

Question 9

Actions of Extensor Carpi Radialis Longus

Answer 9

1. extension of the wrist
2. Abduction (radial deviation) of the hand

Question 10

Origin of Extensor Carpi Radialis Brevis

Answer 10

From the front of the lateral epicondyle of the humerus (common extensor origin)

Question 11

Insertion of Extensor Carpi Radialis Brevis

Answer 11

Into the back of the base of the 3rd metacarpal bone

Question 12

Nerve supply of Extensor Carpi Radialis Brevis

Answer 12

Posterior Interosseous Nerve (the deep branch of radial nerve)
Supplies muscle before it pierces supinator muscle

Question 13

Actions of Extensor Carpi Radialis Brevis

Answer 13

1. Extension of the wrist
2. Abduction (radial deviation of the hand)

Question 14

Origin of Extensor Digitorum

Answer 14

From the front of the lateral epicondyle of the humerus (common extensor origin)

Question 15

Insertion of Extensor Digitorum

Answer 15

1. Middle slip inserts into the base of the middle phalanx
2. Two collateral slips are inserted into the base of the terminal phalanx

on the medial 4 fingers

Question 16

Nerve supply of Extensor Digitorum

Answer 16

Posterior Interosseous nerve

Question 17

Actions of Extensor Digitorum

Answer 17

1. Extension of the MP and the IP joints of the medial 4 fingers
2. Extension of the wrist

Question 18

Origin of Extensor Digiti Minimi

Answer 18

From the front of the lateral epicondyle of the humerus (common extensor origin)

Question 19

Insertion of Extensor Digiti Minimi

Answer 19

By a tendon which joins extensor expansion of the little finger

Question 20

Nerve supply of Extensor Digiti Minimi

Answer 20

Posterior Interosseous Nerve

Question 21

Actions of Extensor Digiti Minimi

Answer 21

1. Extension of the joints of the moss have)
2. Extension of the wrist joint

Question 22

Origin of Extensor Carpi Ulnaris

Answer 22

1. From the front of the lateral epicondyle of the humerus
2. From the posterior border of ulna (by the ulnar aponeurosis)

Question 23

Insertion of Extensor Carpi Ulnaris

Answer 23

Into the back of the base of the 5th metacarpal bone

Question 24

Nerve supply of Extensor Carpi Ulnaris

Answer 24

Posterior Interosseous Nerve

Question 25

Actions of Extensor Carpi Ulnaris

Answer 25

Extension and adduction of the hand

Question 26

Origin of Anconeus

Answer 26

From the back of the lateral epicondyle of the humerus

Question 27

Insertion of Anconeus

Answer 27

Into the lat surface of olecranon process and the upper 1⁄4 of posterior border of ulna.

Question 28

Nerve supply in Anconeus

Answer 28

Radial nerve (by a branch passing through medial head of triceps )

Question 29

Actions of Anconeus

Answer 29

Extension of the elbow joint