Hand Muscles

Question 1

Abductor Pollicis Brevis

Answer 1

O:
Flexor retinaculum
Tubercles of scaphoid and trapezium

I:
Lateral side of base of proximal phalanx of thumb

A:
Abducts thumb and helps oppose it

N:
Recurrent branch of the median n (C8, T1)

Question 2

Flexor Pollicis Brevis

Answer 2

O:
Superficial head–> flexor retinaculum and tubercle of trapezium
Deep head–> floor of carpal tunnel

I:
Lateral side of base of proximal phalanx of thumb

A:
Flexes thumb

N:
Superficial head–> recurrent branch of median n (C8, T1)
Deep head–> deep branch of ulnar n (C8, T1)

Question 3

Opponens Pollicis

Answer 3

O:
Flexor retinaculum
Tubercle of trapezium

I:
Lateral side of base of proximal phalanx of thumb

A:
Opposes thumb toward the center of the palm
Rotates it medially

N:
Recurrent branch of median n (C8, T1)

Question 4

Adductor Pollicis

Answer 4

O:
Oblique head–> bases of metacarpals 2 and 3, capitate and adjacent carpal bones
Transverse head–> anterior surface of 3rd metacarpal

I:
Medial side of base of proximal phalanx of thumb

A:
Adducts thumb toward middle digit

N:
Deep branch of ulnar n (C8, T1)

Question 5

Abductor Digiti Minimi

Answer 5

O:
Pisiform

I:
Medial side of base of proximal phalanx of digit 5

A:
Abducts digit 5

N:
Deep branch of ulnar n (C8,T1)

Question 6

Flexor Digiti Minimi Brevis

Answer 6

O:
Hook of the hamate
Flexor retinaculum

I: Medial side of base of proximal phalanx of 5th digit

A:
Flexes proximal phalanx of digit 5

N:
Deep branch of ulnar n (C8,T1)

Question 7

Opponens Digiti Minimi

Answer 7

O:
Hook of hamate
Flexor retinaculum

I:
Medial border of 5th metacarpal

A:
Draws 5th MC anteriorly and rotates it, bringing the 5th digit into opposition with the thumb

N:
Deep branch of ulnar n (C8, T1)

Question 8

Lumbricals 1 and 2

Answer 8

O:
Lateral 2 tendons of the flexor digitorum profundus (index and middle)

I:
Lateral sides of extensor expansions of digits 2 and 3

A:
Flex digits at MCP joint

N: 
Median nerve (C8, T1)

Question 9

Lumbricals 3 and 4

Answer 9

O:
Medial 2 tendons of FDP (ring and little)

I:
Lateral sides of extensor expansions of digits 4 and 5

A:
Flex digits at MCP joint
Extend IP joints

N:
Deep branch of ulnar n (C8, T1)

Question 10

Dorsal Interosseus 1-4

Answer 10

O:
Adjacent sides of 2 MC bones

I:
Extensor expansions
Bases of proximal phalanges of digits 2-4 (index, middle, ring)
Middle finger has two insertions

A:
Abducts digits
Assist lumbricals in extension at IP joints

N:
Deep branch of ulnar n (C8, T1)

Question 11

Palmar Interosseus 1-3

Answer 11

O:
Palmar surfaces of 2nd, 4th, 5th MC

I:
Extensor expansions and bases of proximal phalanges of digits 2,4,5 (index, ring, little)

A:
Adduct digits, assist lumbricals in flexion at MCP

N:
Deep branch of ulnar n (C8, T1)