OINA: Back/Shoulder/Triceps (Hand muscles)

Question 1

Palmaris Brevis

Answer 1

O: Flexor Retinaculum, Palmar Aponeurosis

I: Skin of palm

N: Superficial branch of ulnar nerve C8,T1

A: Corrugates skin to improve grip of palm

Question 2

Lumbricals (4)

Answer 2

O: Tendons of flexor digitorum profundus

I: Extensor expansion of medial four fingers

N: 1st & 2nd (lateral two) median nerve; 3rd & 4th (medial two) ulnar nerve

A: Flex metacarpophalangeal joints & extend interphalangeal joint of fingers except thumb

Question 3

Palmar Interossei (4)

Answer 3

O: First arise from base of 1st metacarpal; remaining three from anterior surface of shafts of 2nd, 4th & 5th metacarpals

I: Proximal phalanges of thumb & index, ring & little fingers & dorsal extensor expansion of each finger

N: Deep branch of ulnar nerve C8,T1

A: Palmar interossei adduct finger toward center of third finger

Question 4

Dorsal Interossei (4)

Answer 4

O: Contiguous sides of shafts of metacarpal bones

I: Proximal phalanges of index, middle, ring fingers & dorsal extensor expansion

N: Deep branch of ulnar nerve C8,T1

A: Dorsal interossei abducts fingers from center of third finger: both palmar & dorsal flex metacarpophalangeal joints & extend IP joints

Question 5

Abductor Pollicis Brevis

Answer 5

O: Scaphoid, Trapezium, & Flexor retinaculum

I: Base of proximal phalanx of thumb

N: Median Nerve C8,T1

A: Abduction of thumb

Question 6

Flexor Pollicis Brevis

Answer 6

O: Flexor retinaculum

I: Base of proximal phalanx of thumb

N: Median Nerve C8, T1

A: Flexes mcp jt. of thumb

Question 7

Opponens Pollicis

Answer 7

O: Flexor Retinaculum

I: Shaft of metacarpal bone of thumb

N: median nerve C8,T1

A: Pulls thumb medially & forward across palm

Question 8

Adductor Pollicis

Answer 8

O: Oblique head - 2nd & 3rd metacarpal bones
Transverse head - 3rd metacarpal bone

I: Base of proximal phalanx of thumb

N: Deep branch of ulnar nerve C8,T1

A: Adduction of thumb

Question 9

Abductor digiti minimi

Answer 9

O: Pisiform

I: Base of proximal phalanx of little finger

N: Deep branch of ulnar nerve C8,T1

A: Abducts little finger

Question 10

Flexor digiti minimi

Answer 10

O: Flexor retinaculum

I: Base of proximal phalanx of little finger

N: Deep branch of ulnar nerve C8,T1

A: Flexes little finger

Question 11

Opponens digiti minimi

Answer 11

O: Flexor retinaculum

I: Medial border of 5th metacarpal bone

N: Deep branch of ulnar nerve C8,T1

A: Pulls 5th metacarpal forward as in cupping the palm