Hand Flashcards

1
Q

what occurs when metacarpals are injured?

A

Ventral displacement: pulled anteriorly by interossei muscles

Common injury bc hands are used a lot

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are the joints of the hand?

A
  1. carpometacarpal joints
  2. MP joints
  3. IP joints
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are the muscles of the 3 layers of the extrinsic muscles of the hand?
where do they insert?

A
  1. superficial layer: palmaris longus (fuses with retinaculum and continues to fingers)
  2. intermediate layer: flexor digitorum superficialis (bifurcates at the medial phalange and inserts on the middle phalange of the medial 4 digits)
  3. deep layer: Flexor digitorum profundus (Inserts on the distal phalange) + Flexor pollicis longus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are the intrinsic muscles of the hand?

A
  1. thenar muscles
  2. lumricals
  3. hypothenar muscles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what are the thenar muscles?

what is their action?

A
  1. Opponens pollicis (deep to APB & FPB)
  2. Abductor pollicis brevis
  3. Flexor pollicis brevis
  4. Adductor pollicis (not always grouped bc it has diff. innervation) DRAGON WITH 2 HEADZ
    a. Oblique head
    b. Transverse head

action: move thumb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what are the lumbrical muscles?

what is their action?

A
  1. 1st & 2nd (flex MP, extend IP)
  2. 3rd & 4th (same)
  3. Dorsal interossei 1st & 4th
  4. Palmar interossei 1st & 3rd

action: move pinky

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what are the hypothenar muscles?

what is their action?

A
  1. Abductor digiti minimi (superficial & lateral)
  2. Flexor digiti minimi brevis (superficial & medial)
  3. Opponens digiti minimi (deep to ADM & FDM)
  4. Palmaris brevis: subdermal (muscle under skin)
    a. Very thin running transversely

Movement: not much

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what innervates intrinsic muscles of the hand?

A

median and ulnar nerve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what intrinsic muscles are innervated by median nerve?

A
2 LOAF
o	2 = lumricals 1 & 2
o	L = lumbrical
o	O = opponens pollicis
o	F = flexor pollicis brevis
o	Everything else is ulnar n
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the vasculature of the hand?

how does it travel?

A

all hand muscles supplied by radial and ulnar arteries
o Radial artery travels deep to abductor pollicis longus + enters snuffbox
• Lies on top of scaphoid bone + supplies posterior had

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is the action of the extensor digitorum communis?

A

Common extensor for 4 digits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is the action of the extensor indicis proprius?

A

main extensor of hand but assisted by EDC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what are the intrinsic muscles of the dorsal hand?

A

no muscles

interossei muscles are on PALMER hand

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what are the main nerves of the hand?

A

median nerve (anterior interosseus, recurrent branch, volar branch, palmar cutaneous)

ulnar nerve (superficial + deep branches, palmar cutaneous, dorsal branch, branch from superficial terminal, volar branch)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

how does the median nerve travel?

A

travels deep to bicipital aponeuroses→goes deep alongside flexor digitorum superficialis & pronator teres→wrist where it is attached to the FDS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what happens when the median nerve is injured in the elbow?
what is affected?
what are symptoms?

A

during venipuncture when taking blood, fracture of median epicondyle
o Affects all muscles innervated
o “Hand of benediction:” seen when median n. is damaged. Ask pt to clench fist and only pinky + ring finger clenches or fx’s normally bc they are innervated by the ulnar n

17
Q

what happens when the median nerve is injured in the wrist?
what is affected?
what are symptoms?

A

carpal tunnel syndrome caused by displacement of the lunate bone OR inflammation of the ulnar bursa
• Affects muscles of thenar compartment (thumb in flexion + no opposition)
• Abduction of thumb occurs bc abductor pollicis longus moves thumb

18
Q

what are real life examples of median nerve injury?

A

slitting wrist superficial (laceration)

cutting with knife deep causes damage to recurrent branch of median n.

In skin: sensation lost in parts of digits 2, 3 + 4

19
Q

where is the anterior interosseous nerve?

A

Deep to pronator quadratus. (IS NOT A BRANCH OF THE HAND)

20
Q

how does the recurrent branch of the median nerve travel?

what does it innervate?

A

Travels deep to flexor retinaculum
Innervation: 3 intrinsic aka thenar muscles
o Flexor pollicis brevis (only superficial)
o Opponens pollicis
o Abductor pollicic brevis

21
Q

what does the digital aka volar branches innervate?

A

Innervation of skin: Supplies digits 2, 3 & 4

Innervation of muscles: supplies lumbricals 1 & 2

22
Q

how does the palmar cutaneous branch of the median nerve travel and what does it innervate?

how does carpal tunnel affect it?

A

travels superficial to the flexor retinaculum
• supplies the skin of the radial side of the palm
• carpal tunnel syndrome doesn’t affect this branch bc it doesn’t enter the carpal tunnel

23
Q

how does the ulnar nerve travel?

A

travels medially in arm until it twists around the medial epicondyle (ulnar groove) and emerge into forearm and travels to flexor carpi radialis then travels between 2 layers of retincaulum

24
Q

how does the ulnar nerve enter the hand?

A

Travels in an ulnar sheath with the ulnar artery to enter the hand superficially (not under carpal tunnel)

travels in between volar & transverse carpal ligaments of flexor retinaculum

25
Q

how does the ulnar nerve split in the hand?

A

enters between pisiform and hook of the hamate where it splits into the superficial and deep terminal branches

26
Q

what is the sensory innervation of the hand?

what parts of the hand do they supply?

A

palmar cutaneous n.: arises in forearm and enters the hand
o innervates both the palmar + dorsal skin of the medial part of the hand

dorsal branch: innervate parts of the 4th + 5th digits

branch from superficial terminal: innervate the skin over the hypothenar eminence

volar digital branches: supplies the parts of the 4th + 5th digits

27
Q

what is the motor innervation of the hand?

what muscles do they supply?

A

superficial terminal branch supplies Palmaris brevis then continues as a sensory nerve

deep terminal branch supplies FPB (deep head), AP, ADM, FDMB, ODM, lumbrical 3 + 4, dorsal interossei, palmar interossei

28
Q

where does ulnar nerve injury occur?

A

elbow, distal ulna, wrist

29
Q

what are the symptoms of ulnar nerve injury and what does it affect?

A

symptoms: “claw hand”
o lumbrical parlayzed (aided in extension of Interphalageal joints)
o inability to adducts digits and thumb

affect hypothenar, dorsal + palmar interossei
• can lead to atrophy
• sensory deficits on dorsal and palmar aspect of the hand

30
Q

what else can cause ‘claw hand’?

A

fracture of distal ulnar will also cause “claw hand” but may not see sensory loss