Antebrachial Extensor Muscles

Question 1

Brachioradialis Action

Answer 1

• flex elbow in midpronated position
• assists to supinate and pronate forearm when these movemets are restricted/from end range

Question 2

Brachioradialis PA

Answer 2

lateral supra-epicondylar ridge of humerus

Question 3

Brachioradialis DA

Answer 3

distal lateral radius (proximal to styloid process)

Question 4

Brachioradialis Innervation

Answer 4

radial nerve (C5, C6, C7)

Question 5

Extensor Carpi Radialis Longus/Brevis Action

Answer 5

• extend wrist
• radial deviation
• ECRL: active during fist clenching

Question 6

Extensor Carpi Radialis Longus/Brevis PA

Answer 6

• longus: lateral supra-epicondylar ridge of humerus
• brevis: lateral epicondyle of humerus (common extensor tendon)

Question 7

Extensor Carpi Radialis Longus/Brevis DA

Answer 7

• longus: dorsal base of 2nd metacarpal
• brevis: dorsal base of 3rd metacarpal

Question 8

Extensor Carpi Radialis Longus/Brevis Innervation

Answer 8

radial nerve (C6, C7, C8)

Question 9

Extensor Digitorum Action

Answer 9

extend medial 4 digits (MCP and IP joints)

Question 10

Extensor Digitorum PA

Answer 10

lateral epicondyle of humerus (common extensor tendon)

Question 11

Extensor Digitorum DA

Answer 11

extensor expansions of medial 4 digits

Question 12

Extensor Digitorum Innervation

Answer 12

radial nerve (deep branch) (C7, C8)

Question 13

Extensor Digiti Minimi Action

Answer 13

extend 5th digit (MCP and IP joints)

Question 14

Extensor Digiti Minimi PA

Answer 14

lateral epicondyle of humerus (common extensor tendon)

Question 15

Extensor Digiti Minimi DA

Answer 15

extensor expansion (of 5th digit)

Question 16

Extensor Digiti Minimi Innervation

Answer 16

radial nerve (deep branch) (C7, C8)

Question 17

Extensor Carpi Ulnaris Action

Answer 17

• extend wrist
• ulnar deviation
• active during fist clenching

Question 18

Extensor Carpi Ulnaris PA

Answer 18

lateral epicondyle of humerus (common extensor tendon)

Question 19

Extensor Carpi Ulnaris DA

Answer 19

base of 5th metacarpal

Question 20

Extensor Carpi Ulnaris Innervation

Answer 20

radial nerve (C7, C8)

Question 21

Supinator Action

Answer 21

supinate forearm

Question 22

Supinator PA

Answer 22

lateral epicondyle of humerus, radial collateral ligament (RCL), anular ligament

Question 23

Supinator DA

Answer 23

lateral radius

Question 24

Supinator Innervation

Answer 24

radial nerve (PIN) (C7, C8)

Question 25

Extensor Indicis Action

Answer 25

• extend 2nd digit (MCP joint)
• may assist to extend wrist

Question 26

Extensor Indicis PA

Answer 26

posterior distal ulna, interosseous membrane

Question 27

Extensor Indicis DA

Answer 27

extensor expansion (of 2nd digit)

Question 28

Extensor Indicis Innervation

Answer 28

radial nerve (PIN) (C7, C8)

Question 29

Abductor Pollicis Longus Action

Answer 29

• radially abduct thumb (CMC joint)
• extend thumb (CMC joint)

Question 30

Abductor Pollicis Longus PA

Answer 30

posterior proximal ulna, radius, interosseous membrane

Question 31

Abductor Pollicis Longus DA

Answer 31

base of 1st metacarpal

Question 32

Abductor Pollicis Longus Innervation

Answer 32

radial nerve (PIN) (C7, C8)

Question 33

Extensor Pollicis Longus/Brevis Action

Answer 33

• extend thumb (MCP, CMC joint)
• longus: extend thumb at IP joint

Question 34

Extensor Pollicis Longus/Brevis PA

Answer 34

• longus: posterior ulna, interosseous membrane
• brevis: posterior radius, interosseous membrane

Question 35

Extensor Pollicis Longus/Brevis DA

Answer 35

• longus: base of distal phalanx of thumb
• brevis: base of proximal phalanx of thumb

Question 36

Extensor Pollicis Longus/Brevis Innervation

Answer 36

radial nerve (PIN) (C7, C8)