muscles of the hand

Question 1

palmaris brevis

Answer 1

• paper thin
• connects to palmar aponeurosis (triangular, strong deep fascia of the palm, covers soft tissue & overlies long flexor tendons)

Question 2

3 hypothenal muscles (pinky side)

Answer 2

opponens digiti minimi : roll over thumb
flexor digiti minimi
abductor digiti minimi : abduction

Question 3

4 thenar muscles (thumb side)

Answer 3

Pollicis = “of the thumb”

flexor pollicis brevis : help with flexion
opponens pollicis : helps with opposition (thumb to pinky)
abductor pollicis brevis : abduction

adductor pollicis : 2 heads, Adduction

Question 4

adductor pollicis (thenar muscle)

Answer 4

transverse head : more distal, larger
oblique head

Question 5

interossei

Answer 5

innervation : deep branch of ulnar nerve (C8,T1)

action :

(dorsal 1-4) abducts 2nd-4th fingers from axial line (imaginary line down 3rd , helps lumbricals flex metacarpophalangeal joints and extend interphalangeal joints DAB dorsal abduct

(Palmar 1-3) : adduct 2nd, 4th and 5th fingers toward axial line, assists lumbricals flex metacarpophalangeal joints and extend interphalangeal joints PAD Palmar adduct

proximal :

(Dorsal 1-4) adjacent sides of two metacarpals (as bipinnate muscles)

(palmar 1-3) palmar surfaces of 2nd, 4th, and 5th metacarpals (unipennate muscles)

Distal :

(Dorsal 1-4) bases of proximal phalanges; extensor expansions of 2nd-4th fingers

(Palmar 1-3) bases of proximal phalanges; extensor expansions of 2nd, 4th and 5th fingers

Question 6

Answer 6

opponens pollicis

• *proximal** : flexor retinaculum and tubercles of scaphoid and trapezium
• *distal** : lateral side of 1st metacarpal
• *action** : to oppose thumb, it draws 1st metacarpal medially to centre of palm and rotates it medially
• *innervation** : recurrent branch of median nerve (C8, T1)

Question 7

Answer 7

abductor pollicis brevis (APB)

proximal: flexor retinaculum and tubercles of scaphoid and trapezium

distal : lateral side of base of proximal phalanx of thumb

action : abducts thumb; helps oppose it

innervation: recurrent branch of median nerve (C8, T1)

Question 8

Answer 8

flexor pollicis brevis (superficial and deep head)

proximal: flexor retinaculum and tubercles of scaphoid and trapezium

distal: lateral side of base of proximal phalanx of thumb

action: flexes thumb

innervation:

superficial head: recurrent branch of median nerve

deep head: deep branch of ulnar nerve

Question 9

Answer 9

adductor pollicis

proximal :

oblique head: bases of 2nd and 3rd metacarpals, capitate, adjacent carpals

transverse head: anterior surface of shaft of 3rd metacarpal

distal: medial side of base of proximal phalanx of thumb

action: adducts thumb toward lateral border of palm

innervation: deep branch of ulnar nerve (C8, T1)

Question 10

Answer 10

abductor digiti minimi

proximal: pisiform

distal : medial side of base of proximal phalanx of 5th finger

action : abducts 5th finger; assists in flexion of its proximal phalanx

innervation : deep branch of ulnar nerve

Question 11

flexor digiti minimi brevis (FDMB)

Answer 11

proximal : hook of hamate and flexor retinaculum

distal: medial side of base of proximal phalanx of 5th finger

action : flexes proximal phalanx of 5th finger

innervation : deep branch of ulnar nerve (C8, T1)

Question 12

Answer 12

opponens digiti minimi

proximal : hook of hamate and flexor retinaculum

distal : medial border of 5th metacarpal

action : draws 5th metacarpal anterior and rotates it, bringing 5th finger into opposition with thumb

innervation : deep branch of ulnar nerve (C8, T1)

Question 13

Answer 13

lumbricals

proximal : tendons of flexor digitorum profundus

distal : lateral sides of extensor expansions of 2nd-5th fingers

action : flex metacarpophalangeal joints; extend interphalangeal joints of 2nd-5th fingers

innervation :

1 and 2 = median nerve (C8,T1)

3 and 4 =deep branch of ulnar nerve (C8,T1)

Question 14

see lecture 17 for attachments of posterior/anterior forearm muscles

Question 15

arteries and veins of hand

Answer 15

ulnar artery and radial arteries provide all the blood to the hand

ulnar artery enters anteriorly to the Flexor retinaculum between the pisiform and the hook of hamate via the ulnar canal. main contributor to the superficial palmar arch

radial artery main supplier of deep palmar arch (superficial Palmar arch goes deeper)

Question 16

nerves of the hand

Answer 16

median, ulnar and radial nerves supply the hand

median nerve : supplies 2 and a Half thenar muscles and the 1st and 2nd lumbricals

ulnar nerve : gives off a dorsal (cutaneous) branch which supplies medial half of the dorsal of the hand, the 5th finger and the medial half of the 4th finger. Also gives off a palmar cutaneous branch which supplies skin on the median side of the palm

radial nerve supplies no hand muscles

look at lecture 17 pictures and draw