Wrist and Hand Flashcards Preview

Analysis of Movement > Wrist and Hand > Flashcards

Flashcards in Wrist and Hand Deck (54)
Loading flashcards...
1
Q

Why is there more flexion in the wrist (85 deg) than extension (25 deg)?

A

because of the palmar tilt (10 deg posterior) at the end of the radius
- the carpal bones run into the radius quicker when they do extension vs. flexion

2
Q

Through what bone is the axis of rotation for the wrist?

A

capitate

3
Q

What are the top three fractured carpal bones?

A

1) scaphoid
2) lunate (1st most dislocated)
3) triquetrum

4
Q

Name the bones in order, looking from your palmar side and listing the bottom row then top row, radius to ulna.

A

bottom row: scaphoid, lunate, triquetrum, pisiform

top row: trapezium, trapezoid, capitate, hamate

5
Q

What’s the most moveable carpal bone?

A

lunate, making it the most dislocated bone

6
Q

Which side of the carpal bones is more moveable, medial or lateral?

A

medial is more moveable

7
Q

The motions at the wrist include what two joints?

A

1) radiocarpal (lunate moving on radius)

2) midcarpal (capitate moving on lunate)

8
Q

The radiocarpal joint has what basic arthrokinetic rule?

A

convex on concave

9
Q

What gives stability to the wrist?

A

collateral ligaments and intercarpal ligaments

10
Q

What carpal bone does Kienbock’s disease involve? What happens? How will the patient present?

A
  • kienbock’s disease = avascular necrosis of the lunate, due to trauma or compression of bone
  • patient presents with swelling, pain, and decreased ROM
11
Q

Where do most wrist fractures occur from breaking a fall?

A

at the waist of the scaphoid bone, since the styloid process of the radius runs right up into it

12
Q

How many degrees of ulnar and radial deviation can we get?

A
ulnar = 40 deg
radial = 20 deg
13
Q

What allows us to get more ulnar deviation than radial?

A
  • b/c the radius directly articulates w/ carpal bones and the ulna doesn’t
  • due to ulnar tilt of radius
14
Q

What are the degrees needed of ulnar/radial deviation to complete almost all ADLs?

A

30 degrees for ulnar deviation, 10 radial deviation

15
Q

How much flexion/extension do you need at the wrist to complete most ADLs?

A

40 degrees either way

16
Q

Describe the arthrokinematics of the radiocarpal joint for flexion/extension.

A

radiocarpal:

  • flexion = palmar roll of lunate onto radius, dorsal slide
  • extension = dorsal roll, palmar slide
17
Q

Describe the arthrokinematics of the midcarpal joint for flexion/extension.

A

midcarpal:

  • flexion = palmar roll of capitate on lunate, dorsal slide
  • extension = dorsal roll, palmar slide
18
Q

In flexion and extension, from which joint (midcarpal or radiocarpal) does most motion come from?

A
  • split 50/50 for flex and extend

* for ulnar and radial deviation though, it’s 60% MIDCARPAL

19
Q

Describe the arthrokinetmatics of ulnar deviation.

A

1) lunate rolls ulnarly on radius, slides radially

2) capitate rolls ulnarly, slides radially

20
Q

At what position do we have the most grip strength?

A

30-35 degrees of wrist extension, 5 degrees ulnar deviation

21
Q

What happens to the lunate in volar intercalated segment instability (VISI)?

A

lunate displaced palmarly, angle to scaphoid is less than 30 (zig-zag deformity)

22
Q

T/F: The longer moment arm a muscle has, perpendicular to the axis of the muscle it’s acting on, the better it’s able to act on that muscle.

A

true

23
Q

T/F: The wrist extensors are stronger than the wrist flexors.

A

false, wrist flexors are stronger due to more CSA

24
Q

When the lunate creates an angle with the scaphoid that is greater than 60 deg, what kind of carpal instability has occurred?

A

dorsal intercalated segment instability (DISI)

25
Q

T/F: During wrist flexion, you have passive insufficiency of the wrist extensors.

A

true; too stretched to give full ROM

26
Q

T/F: During wrist flexion, you have active insufficiency of the wrist flexors.

A

true; too shortened to produce full flexion force

27
Q

What two muscles synergistically flex the wrist, allowing straight wrist flexion with no deviation?

A

flexor carpi ulnaris and radialis

28
Q

T/F: You have more ulnar deviators than radial deviators.

A

false, more radial: they do 15% greater isometric torque than ulnar deviators

29
Q

Which digits are more rigid?

A

2-3 are rigid, 4-5 give a lot of movement (as well as the thumb)

30
Q

What bones are moving on each other at the thumb joint?

A

metacarpal moves on the trapezium in the saddle joint

31
Q

Do the longitudinal/transverse diameters of the thumb follow the same longitudinal/transverse diameters of the SC, arthrokinematic wise?

A

yes: longitudinal goes in opposite ways, transverse goes in same way

32
Q

Adduction and abduction of the thumb moves in what diameter?

A

ad/ab = longitudinal diameter, so convex on concave

33
Q

Flexion and extension of the thumb occur in what diameter?

A

flex/extend = transverse diameter, so concave on convex

34
Q

Describe the arthrokinematics in the flexion/extension of the thumb.

A
flex = concave metacarpal rolls ulnarly, slides ulnarly
extend = rolls radially, slides radially
35
Q

Do you get more motion in digit abduction when the fingers are flexed or extended?

A

fingers extended gives you more motion to do ad/abduction

36
Q

On what axis does wrist ulnar and radial deviation occur?

A

about the AP axis

37
Q

T/F: Extensor carpi ulnaris is better at extension than ulnar deviation.

A

false: ECU is best at ulnar deviation due to a longer moment arm to the ML axis

38
Q

T/F: The wrist flexors have 2x the CSA of the extensors.

A

true

39
Q

What muscle produces the greatest flexor torque of the three main wrist flexors?

A

FCU

40
Q

What is the purpose of having pulleys in the hands?

A

to hold down the tendons; although these can get thick and cause pain in digits during motion

41
Q

Which pulley is the most important? Why?

A

A1 @ MCP; it’s thicker and more fibrous, so tendon can push its way through the pulley and cause trigger finger

42
Q

What is the normal range of motion at the IP joints?

A

70 deg flexion, 30 deg extension

43
Q

What are the arthrokinematics for all MCP joints in the hand, including IP on MCP?

A

proximal phalange moves on metacarpal, motion is in same directions since they’re all concave on convex

44
Q

Can the MCP of the thumb do ab and adduction, like the MCP of the fingers?

A

no, thumb just does flexion/extension

45
Q

What is the position of function for the hand?

A

think of the splint picture: prevent contractures by keeping hand in slight extension; UD; MCP, DIP, PIP flexion; thumb abduction

46
Q

What’s the difference between extrinsic and intrinsic plus positions?

A

1) extrinsic plus: use superficialis and profundus, and extensor digitorum, to get bear claw hand
2) intrinsic plus: use lumbricals and interossei to get lumbrical action

47
Q

What muscle offsets extensor digitorum while it extends the IPs so that hyperextension at the wrist doesn’t occur?

A

flexor carpi radialis

48
Q

For a low-level fist, what muscle is activated first?

A

first, profundus, then superficialis

49
Q

What osteokinematics need to happen during power grip?

A
  • flexed fingers (esp. 4 and 5)
  • adducted and flexed thumb
  • DAB interossei
  • slight WE and UD
50
Q

Compare boutonniere deformity and swan neck deformity.

A

boutonniere = flexed PIP, extended DIP

swan neck = extended PIP, flexed DIP

51
Q

Why does ulnar drift occur?

A

thumb adducts and the interossei can’t resist that motion (the connective tissue they attach to is broken down), so those fingers begin to move ulnarly like the thumb

52
Q

Abductor pollicis brevis is used in what grip?

A

precision grip, to abduct thumb

53
Q

What does “power key” or “power pinch” involve?

A

DAB to abduct 1st digit toward thumb, adductor pollicis to bring thumb to lateral border of first digit

54
Q

What causes boutonniere deformity?

A

central tendon on dorsum of digit tears