Superficial and Deep Forearm Extensors

Question 1

Supinator origin

Answer 1

Lateral epicondyle of humerus, supinator fossa, crest of ulna

Question 2

Supinator insertion

Answer 2

Lateral, posterior and anterior surface of proximal third of radius

Question 3

Supinator innervation

Answer 3

Deep branch of radial nerve

Question 4

Supinator blood supply

Answer 4

Radial recurrent artery

Question 5

Abductor pollicis longus origin

Answer 5

Posterior surface of ulna, radius, interosseous membrane

Question 6

Abductor pollicis longus insertion

Answer 6

Base of 1st metacarpal

Question 7

Abductor pollicis longus innervation

Answer 7

Posterior interosseous nerve

Question 8

Abductor pollicis longus action

Answer 8

Abduction of 1st digit, extension of MCP joint, extension at the wrist

Question 9

Extensor pollicis brevis origin

Answer 9

Posterior surface of radius and interosseous membrane

Question 10

Extensor pollicis brevis insertion

Answer 10

Base of proximal phalanx of 1st digit

Question 11

Extensor pollicis brevis innervation

Answer 11

Posterior interosseous nerve

Question 12

Extensor pollicis brevis blood supply

Answer 12

Posterior interosseous artery

Question 13

Extensor pollicis brevis action

Answer 13

Extension of MCP joint at 1st digit

Question 14

Extensor pollicis longus origin

Answer 14

Posterior surface of middle of third of ulna, interosseous membrane

Question 15

Extensor pollicis longus insertion

Answer 15

Base of distal phalanx of the 1st digit

Question 16

Extensor pollicis longus innervation

Answer 16

Posterior interosseous nerve

Question 17

Extensor pollicis longus blood supply

Answer 17

Posterior interosseous artery

Question 18

Extensor pollicis longus action

Answer 18

Extension of MCP and IP joint of 1st digit

Question 19

Extensor pollicis longus action

Answer 19

Extension at the wrist

Question 20

Extensor indicis origin

Answer 20

Posterior surface of ulna, interosseous membrane

Question 21

Extensor indicis innervation

Answer 21

Posterior interosseous nerve

Question 22

Extensor indicis blood supply

Answer 22

Posterior interosseous artery

Question 23

Extensor indicis action

Answer 23

Extension at the MCP and IP joints of 2nd digit, extension at hand at the wrist

Question 24

Supination at the wrist

Answer 24

Biceps brachii, supinator

Question 25

Pronation at the wrist

Answer 25

Pronator quadratus, pronator teres, flexor carpi radialis (brachioradialis)

Question 26

Flexion at the wrist

Answer 26

Flexor carpi radialis, ulnaris, palmaris longus, abductor pollicis longus

Question 27

Extension at the wrist

Answer 27

Extensor carpi radialis longus and brevis, extensor carpi ulnaris

Question 28

Abduction at the wrist

Answer 28

Extensor carpi radialis longus, flexor carpi radialis brevis, extensor pollicis longus

Question 29

Adduction

Answer 29

Extensor carpi ulnaris and flexor carpi ulnaris

Question 30

When is the anatomical snuff box visible?
What artery lies on it?
Carpals that can be felt in the snuff box?

Answer 30

• When the thumb is abducted
• Radial artery
• Scaphoid and trapezium

Question 31

Medial border of the suff box

Answer 31

tendon of the extensor pollicis longus

Question 32

Lateral border

Answer 32

Pair of parallel tendons of extensor pollicis brevis and abductor pollicis longus

Question 33

Intertendinous connections

Answer 33

Restrict independent extension of the fingers

Question 34

Extensor expansions

Answer 34

Distal ends of the metacarpals the four tendons of extensor digitorum flatten to form

Question 35

Retinacular ligament

- Location?

Answer 35

• Proximal phalanx –> middle phalanx –> two interphalangeal joints (obliquely)
• During flexion of the distal interphalangeal joint, the RL becomes right

Question 36

Sole control of the index finger?

Acts with?

Answer 36

Extensor indicis

Extensor digitorum to extend

Question 37

3 muscles that control the thumb?

Answer 37

APL, EPB, EPL