Hand Muscles

Question 1

What are the 3 areas of muscle in the hand?

Answer 1

Thenar eminence, Hyperthenar eminence and intermediate muscles

Question 2

Abductor Pollicis Brevis

Answer 2

Origin
- Tubercles of scaphoid and trapezium and adjacent flexor retinaculum

Insertion
- Proximal phalanx and extensor hood of thumb

Nerve Supply
- Median nerve (C8, T1)

Action
- Abducts thumb at metacarpophalangeal joint and carpometacarpal joint

Question 3

Flexor Pollicis Brevis

Answer 3

Origin
- Tubercles of trapezium and flexor retinaculum

Insertion
- Proximal phalanx of thumb

Nerve Supply
- Median nerve (C8, T1)

Action
- Flexes thumb at metacarpophalangeal joint and carpometacarpal joint

Question 4

Opponens Pollicis - sits deep to APB and FPB

Answer 4

Origin
- Tubercles of trapezium and flexor retinaculum

Insertion
- Lateral margin and adjacent palmar surface of metacarpal I

Nerve Supply
- Median nerve (C8, T1)

Action
- Medially rotates thumb

Question 5

Adductor Pollicis - sits in the web space

Answer 5

Origin
- Transverse head - MC III
- Oblique head - capitate and bases
of MC II and III

Insertion
- Base of proximal phalanx and extensor hood of thumb

Nerve Supply
- Ulnar nerve (C8, T1)

Action
- Adducts thumb

Question 6

Abductor Digiti Minimi - most superficial in hypothenar eminence

Answer 6

Origin
- Pisiform
- Pisohamate ligament
- Tendon of Flexor Carpi Ulnaris

Insertion
- Proximal phalanx of little finger

Nerve Supply
- Ulnar nerve (C8, T1)

Action
- Abducts little finger at metacarpophalangeal joint and flexion

Question 7

Flexor Digit Minimi - sits next to ADM

Answer 7

Origin
- Hook of hamate
- Flexor retinaculum

Insertion
- Proximal phalanx of little finger

Nerve Supply
- Ulnar nerve (C8, T1)

Action
- Flexes little finger at MCP joint

Question 8

Opponens Digit Minimi

Answer 8

Origin
- Hook of hamate and flexor retinaculum

Insertion
- Sits on medial aspect of MC V

Nerve Supply
- Ulnar nerve (C8, T1)

Action
- Laterally rotates MC V

Question 9

Palmaris Brevis - not strictly in the hypothenar eminence

Answer 9

Origin
- Palmar aponeurosis = triangular deep fascia that covers the palm
- Flexor retinaculum

Insertion
- Dermis skin on the medial margin of the hand

Nerve Supply
- Ulnar nerve (C8, T1)

Action
- Improves grip

Question 10

Lumbricals - 4 of them

Answer 10

Origin
- Tendons of Flexor Digitorum Profundus

Insertion
- Extensor hoods of index, ring, middle and little fingers (one associated with each finger)

Nerve Supply
- Medial two by the deep branch of the ulnar nerve
- Lateral two by the digital branches of the median nerve

Action
- Flex metacarpophalangeal joints
- Extends interphalangeal joints

Question 11

Palmar Interossei - MC III doesn’t have a PI

Answer 11

Origin
- Sides of metacarpals

Insertion
- Extensor hoods of the thumb, index, ring, and little fingers and the proximal phalanx of thumb

Nerve Supply
- Ulnar nerve (C8, T1)

Action
- Adduction of the thumb, index, ring and little fingers at the metacarpophalangeal joints

Question 12

Dorsal Interossei - the most dorsal of the intrinsic muscles

Answer 12

• Origin
  
  • Adjacent sides of metacarpals
• Insertion
  
  • Extensor hood and base of proximal phalanges of index, middle and ring fingers
• Nerve Supply
  
  • Ulnar nerve (C8, T1)
• Action
  
  • Abduction of index, middle and ring fingers at the metacarpophalangeal joints