Intrinsic Hand Muscles

Question 1

The fleshy part at the base of the thumb, which is made up of 3 muscles.

Answer 1

Thenar Eminence

Question 2

What are the 3 thenar muscles?

Answer 2

1) Opponens Pollicis
2) Abductor Pollicis Brevis
3) Flexor Pollicis Brevis

Question 3

Proximal Attachment: flexor retinaculum and tubercle of trapezium
Distal Attachment: lateral side of 1st MC

Answer 3

Opponens Pollicis

Question 4

What are the 2 actions of opponens pollicis?

Answer 4

1) Thumb Flexion (component of opposition)
2) Thumb Medial Rotation (component of opposition)

Question 5

Proximal Attachment: flexor retinaculum and tubercles of scaphoid and trapezium
Distal Attachment: lateral side of base of proximal phalanx of thumb

Answer 5

Abductor Pollicis Brevis

Question 6

What is the action of abductor pollicis brevis?

Answer 6

Thumb Abduction (Assist in Opposition)

Question 7

Proximal Attachment: flexor retinaculum and tubercles of scaphoid and trapezium
Distal Attachment: lateral side of base of proximal phalanx of thumb

Answer 7

Flexor Pollicis Brevis

Question 8

What is the action of flexor pollicis brevis?

Answer 8

Thumb Flexion (Assist in Opposition)

Question 9

The fleshy part at the base of the 5th digit, which is made up of 4 muscles.

Answer 9

Hypothenar Eminence

Question 10

What are the 4 hypothenar muscles?

Answer 10

1) Opponens Digiti Minimi (most deep)
2) Abductor Digiti Minimi (most superficial)
3) Flexor Digiti Minimi Brevis
4) Palmaris Brevis

Question 11

Proximal Attachment: hook of hamate and flexor retinaculum
Distal Attachment: medial border of 5th MC

Answer 11

Opponens Digiti Minimi

Question 12

What is the action of opponens digiti minimi?

Answer 12

Draws 5th MC anteriorly and rotates it to oppose thumb

Question 13

Proximal Attachment: pisiform
Distal Attachment: medial side of base of proximal phalanx of 5th digit

Answer 13

Abductor Digiti Minimi

Question 14

What is the action of abductor digiti minimi?

Answer 14

5th Digit Abduction

Question 15

Proximal Attachment: hook of hamate and flexor retinaculum
Distal Attachment: medial side of base of proximal phalanx of 5th digit

Answer 15

Flexor Digiti Minimi Brevis

Question 16

What is the action of flexor digiti minimi brevis?

Answer 16

5th Digit Flexion (Proximal Phalanx)

Question 17

Proximal Attachment: flexor retinaculum and palmar aponeurosis
Distal Attachment: skin on medial side of palm

Answer 17

Palmaris Brevis

Question 18

Palmaris brevis ________ the skin on the medial side of the palm and covers/protects the _____ nerve and artery.

Answer 18

Wrinkles
Ulnar

Question 19

Proximal Attachment: base of 2nd MC, trapezoid and capitate (oblique head) and shaft of 3rd MC (transverse head)
Distal Attachment: medial side of base of proximal phalanx of thumb

Answer 19

Adductor Pollicis

Question 20

What is the action of adductor pollicis?

Answer 20

Thumb Adduction

Question 21

Which muscle forms the bulk of the thumb web space on the anterior surface?

Answer 21

Adductor Pollicis

Question 22

Proximal Attachment: FDP tendon
Distal Attachment: extensor expansion of 2nd-5th digits

Answer 22

Lumbricals

Question 23

What are the 2 actions of the lumbricals in the hand?

Answer 23

1) MCP Flexion
2) IP Extension

Question 24

Proximal Attachment: adjacent sides of two MC bones
Distal Attachment: extensor expansions and bases of proximal phalanges of 2nd-4th digits

Answer 24

Dorsal Interossei

Question 25

What is the action of the dorsal interossei in the hand?

Answer 25

Abduction of Digits

Question 26

Proximal Attachment: palmar surfaces of 2nd, 4th and 5th MCs
Distal Attachment: extensor expansions and bases of proximal phalanges of 2nd, 4th and 5th digits

Answer 26

Palmar Interossei

Question 27

What is the action of the palmar interossei in the hand?

Answer 27

Adduction of Digits