Myology of the thumb and intrinsic muscles of the hand

Question 1

Origin of abductor pollicis brevis?

Answer 1

Flexor retinaculum, tubercles of scaphoid and trapezium

Question 2

Insertion of abductor pollicis brevis?

Answer 2

Radial side proximal surface of thumb

Question 3

Action of abductor pollicis brevis?

Answer 3

Abducts thumb

Question 4

Innervation of abductor pollicis brevis?

Answer 4

Median nerve (T1)

Question 5

Origin of flexor pollicis longus?

Answer 5

Anterior surface of radius, between radial tuberosity and pronator quadratus, and adjacent interosseous membrane

Question 6

Insertion of flexor pollicis longus?

Answer 6

Palmar surface of distal phalanx of thumb

Question 7

Action of flexor pollicis longus?

Answer 7

Flexes the MCP and IP joint of thumb

Question 8

Innervation of flexor pollicis longus?

Answer 8

Anterior interosseous branch of median nerve (C8-T1)

Question 9

Origin of extensor pollicis longus?

Answer 9

Middle third posterior surface of the ulna and adjacent interosseous membrane

Question 10

Insertion of extensor pollicis longus?

Answer 10

Dorsal surface of distal phalanx of thumb

Question 11

Action of extensor pollicis longus?

Answer 11

Extends the CMC, MCP and IP joint of thumb, extends and abducts the RC joint

Question 12

Innervation of extensor pollicis longus?

Answer 12

Posterior interosseous branch of radial nerve (C7-C8)

Question 13

Origin of extensor pollicis brevis?

Answer 13

Middle third posterior surface of the radius and adjacent interosseous membrane

Question 14

Insertion of extensor pollicis brevis?

Answer 14

Dorsal surface base of proximal phalanx of thumb

Question 15

Action of extensor pollicis brevis?

Answer 15

Extend the CMC and MCP joint, extension and radial deviation of the RC joint

Question 16

Innervation of extensor pollicis brevis?

Answer 16

Posterior interosseous branch of radial nerve (C7-C8)

Question 17

Origin of abductor pollicis longus?

Answer 17

Posterior third of the radius and ulna and adjacent interosseous membrane

Question 18

Insertion of abductor pollicis longus?

Answer 18

Radial side, base of first metacarpal of thumb

Question 19

Innervation of abductor pollicis longus?

Answer 19

Posterior interosseous branch of the radial nerve (C7-C8)

Question 20

Action of abductor pollicis longus?

Answer 20

Abducts the thumb

Question 21

Origin of flexor pollicis brevis?

Answer 21

Tubercle of trapezium, trapezoid, and capitate, and flexor retinaculum

Question 22

Insertion of flexor pollicis brevis?

Answer 22

Radial side base of proximal phalanx of thumb

Question 23

Action of flexor pollicis brevis?

Answer 23

Flexes the MCP and CMC joints of the thumb

Question 24

Innervation of flexor pollicis brevis?

Answer 24

Median nerve T1

Question 25

Origin of opponens pollicis?

Answer 25

Tubercle of trapezium and flexor retinaculum

Question 26

Insertion of opponens pollicis?

Answer 26

Whole length of palmar surface of first metacarpal

Question 27

Action of opponens pollicis?

Answer 27

Opposes thumb

Question 28

Innervation of opponens pollicis?

Answer 28

Median nerve (T1)

Question 29

Origin of adductor pollicis?

Answer 29

Oblique Head: bases of 2nd,3rd & 4th metacarpals, trapezoid and capitate bones Transverse head: anterior surface of shaft of 3rd metacarpal

Question 30

Insertion of adductor pollicis?

Answer 30

Medial side of base of proximal phalanx

Question 31

Action of adductor pollicis?

Answer 31

Adducts the thumb

Question 32

Innervation of adductor pollicis?

Answer 32

Ulnar nerve (C8-T1)

Question 33

Origin of 1st palmar interosseous?

Answer 33

Shaft of 1st metacarpal

Question 34

Insertion of 1st palmar interosseous?

Answer 34

Via dorsal digital expansion of EPollL into medial side of base of proximal phalanx with adductor pollicis

Question 35

Action of 1st palmar interosseous?

Answer 35

Adduction of 1st CMC joint Assists in flexion of 1st MCP joint

Question 36

Innervation of 1st palmar interosseous?

Answer 36

Ulnar nerve (C8-T1)

Question 37

Origin of flexor digiti minimi brevis?

Answer 37

Hook of hamate and flexor retinaculum

Question 38

Insertion of flexor digiti minimi brevis?

Answer 38

Base of proximal phalanx of little finger

Question 39

Action of flexor digiti minimi brevis?

Answer 39

Flexes MCP joint of little finger

Question 40

Innervation of flexor digiti minimi brevis?

Answer 40

Ulnar nerve (T1)

Question 41

Origin of abductor digiti minimi?

Answer 41

Pisiform and adjacent ligaments

Question 42

Insertion of abductor digiti minimi?

Answer 42

Ulnar side proximal phalanx of little finger and dorsal digital expansion

Question 43

Action of abductor digiti minimi?

Answer 43

Abducts little finger

Question 44

Innervation of abductor digiti minimi?

Answer 44

Ulnar nerve (T1)

Question 45

Origin of opponens digiti minimi?

Answer 45

Hook of hamate and flexor retinaculum

Question 46

Insertion of opponens digiti minimi?

Answer 46

Palmar surface of 5th metacarpal

Question 47

Action of opponens digiti minimi?

Answer 47

Opposes the little finger

Question 48

Innervation of opponens digiti minimi?

Answer 48

Ulnar nerve (T1)

Question 49

Origin of lumbricals?

Answer 49

Lateral side of flexor digitorum profundus tendons

Question 50

Insertion of lumbricals?

Answer 50

Lateral edge of dorsal digital expansion of same fingers

Question 51

Action of lumbricals?

Answer 51

Flexes the CMC joints and extends the MCP and IP joints

Question 52

Innervation of lumbricals?

Answer 52

Lateral 2: Median nerve (T1), medial 2: ulnar nerve (T1)

Question 53

Origin of palmar interossei?

Answer 53

Shaft of each metacarpal

Question 54

Insertion of palmar interossei?

Answer 54

Dorsal digital expansion and proximal phalanx of same finger

Question 55

Action of palmar interossei?

Answer 55

Adducts all digits except middle finger

Question 56

Innervation of palmar interossei?

Answer 56

Ulnar nerve (T1)

Question 57

Origin of dorsal interossei?

Answer 57

As bipennate muscles, they attach into the adjacent side of each metacarpal

Question 58

Insertion of dorsal interossei?

Answer 58

Dorsal digital expansion and proximal phalanx of the appropriate finger (2nd, 3rd, and 4th digits)

Question 59

Action of dorsal interossei?

Answer 59

Abducts the 2nd, 3rd, and 4th fingers

Question 60

Innervation of dorsal interossei?

Answer 60

Ulnar nerve (T1)