Intrinsic Muscles of the Hand

Question 0

What movement do the thenar muscles perform?

Answer 0

Opposition of the thumb

Question 1

What muscles make up the thenar compartment?

Answer 1

Abductor pollicis brevis, flexor pollicis brevis, and opponens pollicis

Question 2

What is the origin of the opponens pollicis?

Answer 2

Flexor retinaculum and tubercles of scaphoid and trapezium

Question 3

Where does the opponens pollicis insert?

Answer 3

Lateral side of first metacarpal

Question 4

What is the innervation for the opponens pollicis?

Answer 4

Recurrent branch of median nerve (C8, T1)

Question 5

What action does the opponens pollicis perform?

Answer 5

To oppose thumb, it draws 1st metacarpal medially to center of palm and rotates it medially

Question 6

What is the origin of the abudctor pollicis brevis?

Answer 6

Flexor retinaculum and tubercles of scaphoid and trapezium

Question 7

Where does the abductor pollicis brevis insert?

Answer 7

Lateral side of base of proximal phalanx of thumb

Question 8

What is the innervation of the abductor pollicis brevis?

Answer 8

Recurrent branch of median nerve (C8, T1)

Question 9

What action does the abductor pollicis brevis?

Answer 9

Abducts thumb; helps oppose it

Question 10

What is the origin of the flexor pollicis brevis?

Answer 10

Flexor retinaculum and tubercles of scaphoid and trapezium

Question 11

Where does the flexor pollicis brevis insert?

Answer 11

Lateral side of base of proximal phalanx of thumb

Question 12

What is the innervation of the flexor pollicis brevis?

Answer 12

Recurrent branch of median nerve (C8, T1) for superficial head and deep branch of ulnar nerve (C8, T1) for deep head

Question 13

What action does the flexor pollicis brevis perform?

Answer 13

Flexes thumb

Question 14

What muscle makes up the adductor compartment?

Answer 14

Adductor pollicis

Question 15

What is the origin of the adductor pollicis?

Answer 15

Oblique head originates on bases of 2nd and 3rd metacarpals, capitate, adjacent carpals
Transverse head originates on the anterior surface of shaft of 3rd metacarpal

Question 16

Where does the adductor pollicis insert?

Answer 16

Medial side of base of proximal phalanx of thumb

Question 17

What is the innervation of the adductor pollicis?

Answer 17

Deep branch of ulnar nerve (C8, T1)

Question 18

What action does the adductor pollicis perform?

Answer 18

Adducts thumb toward lateral border of palm

Question 19

What muscles make up the hypothenar compartment?

Answer 19

Abductor digiti minimi, flexor digiti minimi brevis, and opponens digiti minimi

Question 20

What is the origin of the abductor digiti minimi?

Answer 20

Pisiform

Question 21

Where does the abductor digiti minimi insert?

Answer 21

Medial side of base of proximal phalanx of 5th finger

Question 22

What is the innervation of the abductor digiti minimi?

Answer 22

Deep branch of ulnar nerve (C8, T1)

Question 23

What action does the abductor digiti minimi perform?

Answer 23

Abducts 5th finger; assists in flexion of its proximal phalanx

Question 24

What is the origin of the flexor digiti minimi brevis?

Answer 24

Hook of hamate and flexor retinaculum

Question 25

Where does the flexor digiti minimi brevis insert?

Answer 25

Medial side base of proximal phalanx of 5th finger

Question 26

What is the innervation of flexor digiti minimi brevis?

Answer 26

Deep branch of ulnar nerve (C8, T1)

Question 27

What action does the flexor digiti minimi brevis perform?

Answer 27

Flexes proximal phalanx of 5th finger

Question 28

What is the origin of the opponens digiti minimi?

Answer 28

Hook of hamate and flexor retinaculum

Question 29

Where does the opponens digiti minimi insert?

Answer 29

Medial border of 5th metacarpal

Question 30

What is the innervation of the opponens digiti minimi?

Answer 30

Deep branch of ulnar nerve (C8, T1)

Question 31

What action does the opponens digiti minimi perform?

Answer 31

Draws 5th metacarpal anterior and rotates it, bringing 5th finger into opposition with thumb

Question 32

What muscles make up the central compartment and are considered short muscles?

Answer 32

The lumbricals

Question 33

What is the origin of lumbricals 1 and 2?

Answer 33

Lateral two tendons of flexor digitorum profundus (as unipennate muscles)

Question 34

Where do lumbricals 1 and 2 insert?

Answer 34

Lateral sides of extensor expansions of 2nd and 3rd fingers

Question 35

What is the innervation of lumbricals 1 and 2?

Answer 35

Median nerve (C8, T1)

Question 36

What action do lumbricals 1 and 2 perform?

Answer 36

Flex metacarpophalangeal joints; extend interphalangeal joints of 2nd and 3rd fingers

Question 37

What is the origin of lumbricals 3 and 4?

Answer 37

Medial three tendons of flexor digitorum profundus (as bipennate muscles)

Question 38

Where do lumbricals 3 and 4 insert?

Answer 38

Lateral sides of extensor expansions of 4th and 5th

Question 39

What is the innervation of lumbricals 3 and 4?

Answer 39

Deep branch of ulnar nerve (C8, T1)

Question 40

What action do lumbricals 3 and 4 perform?

Answer 40

Flex metacarpophalangeal joints; extend interphalangeal joints of 4th and 5th fingers

Question 41

What muscles make up the interosseous compartments and short muscles of the hand?

Answer 41

Dorsal interossei 1-4 and palmar interossei 1-3

Question 42

Where are the dorsal interossei located?

Answer 42

Between the metacarpals

Question 43

Where are the palmar interossei located?

Answer 43

Palmar surface of 2nd, 4th, and 5th metacarpals

Question 44

What is the origin of the dorsal interossei?

Answer 44

Adjacent sides of two metacarpals (as bipennate muscles)

Question 45

Where does the dorsal interossei insert?

Answer 45

Bases of proximal phalanges; extensor expansions of 2nd-4th finger

Question 46

What is the innervation of the dorsal interossei?

Answer 46

Deep branch of ulnar nerve (C8, T1)

Question 47

What action do the dorsal interossei perform?

Answer 47

Abduct 2nd-4th fingers from axial line; act with lumbricals in flexing metacarpophalngeal joints and extending interphalangeal joints

Question 48

What is the origin of the palmar interossei?

Answer 48

Palmar surfaces of 2nd, 4th, and 5th metacarpals (as unipennate muscles)

Question 49

Where do the palmar interossei insert?

Answer 49

Bases of proximal phalanges; extensor expansions of 2nd, 4th, 5th fingers

Question 50

What is the innervation of the palmar interossei?

Answer 50

Deep branch of ulnar nerve (C8, T1)

Question 51

What action do the palmar interossei perform?

Answer 51

Adduct 2nd, 4th, and 5th fingers toward axial line; assist lumbricals in flexing metacarpophalangeal joints and extending interphalangeal joints