24: UE Myology: Hand

Question 1

Abductor pollicis brevis O and I

Answer 1

O: scaphoid, trapezium, flexor retinaculum
I: proximal phalanx of pollux

Question 2

Abductor pollicis brevis A

Answer 2

Abduct pollux, opposition

Question 3

Abductor pollicis brevis N

Answer 3

Recurrent branch of median N

Question 4

Opponens pollicis O and I

Answer 4

O: scaphoid, trapezium, flexor retinaculum (same as abductor pollicis brevis)
I: lateral 1st metacarpal

Question 5

Opponens pollicis N

Answer 5

Recurrent branch of median N

Question 6

What movement can be lost with even a very superficial palm injury resulting in damage to the median N?

Answer 6

Opposition of the thumb

Question 7

Flexor pollicis brevis O and I

Answer 7

O: scaphoid, trapezium, flexor retinaculum
I: proximal phalanx of pollux

Question 8

Flexor pollicis brevis A

Answer 8

Flex 1st metacarpal and proximal phalanges of pollux

Question 9

Flexor pollicix brevis N (two heads)

Answer 9

Superficial head: recurrent branch of median N

Deep head: deep ulnar N

Question 10

Adductor pollicis O and I (two heads)

Answer 10

Oblique head O: capitate, 2nd and 3rd metacarpal bases
Transverse head: 3rd metacarpal
I: proximal phalanx of pollux

Question 11

Adductor pollicis A

Answer 11

Adduct pollux

Question 12

Adductor pollicis N

Answer 12

Deep ulnar N

Question 13

Innervation to hypothenar eminence

Answer 13

Deep ulnar N

Question 14

Abductor digiti minimi O and I

Answer 14

O: pisiform
I: proximal phalanx of 5th digit

Question 15

Abductor digiti minimi A

Answer 15

Abduct 5th digit

Question 16

Flexor digiti minimi brevis O and I

Answer 16

O: hook of hamate, flexor retinaculum
I: proximal phalanx 5th digit

Question 17

Flexor digiti minimi brevis A

Answer 17

Flex 5th digit

Question 18

Opponens digiti minimi O and I

Answer 18

O; hook of hamate, flexor retinaculum

I: medial 5th metacarpal

Question 19

1st and 2nd lumbrical O and I

Answer 19

O: lateral side of lateral 2 flexor digitorum profundus tendons
I: radial aspect of extensor expansion of 2nd and 3rd digits

Question 20

Difference in shape of 1st/2nd vs 3rd/4th lumbricals

Answer 20

1st and 2nd: unipennate

3rd and 4th: bipennate

Question 21

3rd and 4th lumbrical O and I

Answer 21

O: between medial 3 flexor digitorum profundus tendons
I: radial aspect of extensor expansions of 4th and 5th digits

Question 22

Lumbrical A

Answer 22

Flex proximal phalanges, extend intermediate and distal phalanges by tightening extensor expansion

Question 23

1st and 2nd lumbrical innervation vs 3rd and 4th

Answer 23

1st and 2nd: median N

3rd and 4th: deep ulnar N

Question 24

Dorsal interossei O and I

Answer 24

O: adjacent sides to 2 metacarpals (bipennate)
I: proximal phalanges 2-4, extensor expansions

Question 25

Dorsal interossei A

Answer 25

Abducts digits 2-4, flex proximal phalanges, extend intermediate and distal phalanges

Question 26

Dorsal and palmar interossei N

Answer 26

Deep ulnar N

Question 27

Palmar interossei O and I

Answer 27

O: palmar aspect of 2nd, 4th, and 5th metacarpals
I: proximal phalanges 2, 4, 5 + thier extensor expansions

Question 28

Palmar interossei A

Answer 28

Adduct 2,3,5 digits, flex proximal digits and extend intermediate and distal phalanges

Question 29

Two muscle groups involved in the power grip (palm grasp)

Answer 29

Long flexors of the digits + intrinsic hand muscles

Question 30

What muscle group is used for the hook grip?

Answer 30

Long flexors of digits

Question 31

Three groups of muscles active in precision handling grip (like using a pen)

Answer 31

Long flexors, long extensors, intrinsic hand muscles