Wrist and Hand Biomechanics Flashcards Preview

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Flashcards in Wrist and Hand Biomechanics Deck (174)
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1
Q

What is prehension

A

Grip

2
Q

True or False:

You need proximal stability for distal mobility

A

True

3
Q

True or False:

The UE is subservient to the wrist and hand

A

True

4
Q

Is compensation proximally for lost hand function effective

A

Nope

5
Q

How many degrees of freedom does the humeroulnar joint have

A

1

6
Q

During CKC pronation and supination what is moving

A

Ulna rotates on a fixed radius

7
Q

Fewer degrees of freedom means there is more mobility or stability

A

Stability

8
Q

What is AOM

A

Analysis of Motion

9
Q

How can the ulna rotate on the radius during CKC supination and pronation

A

The ulna has no articulation with the wrist

10
Q

Where is the expansion of the radius

A

At the carpus

11
Q

What is the purpose of the expansion of the radius and ulna

A

Attachment of muscles, tendons, and ligaments

12
Q

Where is the ulnar expansion

A

At the humerus

13
Q

The ulna at the carpus is modified for what

A

Radius and hand to rotate

14
Q

The space at the distal end of the ulna is called what

A

Ulnocarpal space

15
Q

What is in the ulnocarpal space

A

Triangular Firbrocartilage Complex (TFC)

16
Q

Where does the stability of the hand come from

A

3rd metacarpal and somewhat the 2nd metacarpal

17
Q

What is the 3rd metacarpal flanked by

A

Mobile segments

18
Q

What is the thenar eminence

A

Thumb side muscularture

19
Q

What is the hypothenar eminence

A

Pink side musculature

20
Q

What muscles are present at the 2nd and 3rd metacarpals to provide stability at the wrist allowing for freedom of movement around the pillar (3)

A
  1. Extensor carpi radialis longus
  2. Extensor carpi radialis brevis
  3. Flexor carpi radialis
21
Q

Which carpal is most inportant

A

Capitate

22
Q

What type of motion occurs at the wrist complex

A

Biaxial

23
Q

What are the planes motion occurs in at the wrist complex

A

Frontal and sagittal

24
Q

What are the sagittal plane motions

A

Flexion and extension

25
Q

What is the range for flexion and extension at the wrist complex

A

Flexion: 80-90
Extension: 70-80

26
Q

What are the frontal plane motions

A

Ulnar and radial deviation

27
Q

What is the range for ulnar and radial deviation

A

Ulnar: 30-35
Radial: 20-25

28
Q

Why is radial deviation less than ulnar deviation

A

Due to the size of the radial styloid

29
Q

What makes up the proximal articulation of the radiocarpal joint

A

Radius and radioulnar disc (TFC)

30
Q

What makes up the distal articulation of the radiocarpal joint

A

Scaphoid, lunate, triquetrium

31
Q

What are the arthronkinematics of the radiocarpal joint

A

Convex scaphoid and lunate moving on a concave distal radius

32
Q

What does the lateral radial facet articulate with and percent of the radiocarpal joint

A

Scaphoid, 46%

33
Q

What does the medial radial facet articulate with and percent of the radiocarpal joint

A

Lunate, 43%

34
Q

What does the inferior radioulnar disc articulate with and percent of the radiocarpal joint

A

Triquetrium, 11%

35
Q

True or False:

There is no formal carpal articulation with the ulna

A

True

36
Q

Is the pisiform included in the radiocarpal joint

A

No

37
Q

What type of bone is the pisiform bone

A

Sesamoid bone

38
Q

What does the pisiform do

A

Increase MA of the flexor carpi ulnaris

39
Q

What does a sesamoid bone do

A

Enhances MA of muscles

40
Q

True or False:

No muscles act directly on the RC joint

A

True

41
Q

What is motion at the radiocarpal joint due to

A

Ligamentous forces distributed and muscles that insert at the distal carpals and metacarpals

42
Q

What 2 motions does the radiocarpal joint contribute to most

A

Flexion and ulnar deviation

43
Q

If someone has flexion and ulnar deviation problems what joint should you focus on

A

Radiocarpal joint

44
Q

True or False:

The midcarpal joint has no isolated capsule

A

True

45
Q

How would you describe the midcarpal joint

A

Interrupted multiarticular surface

46
Q

True or False:

The scaphoid contributes to motion both at the radiocarpal and midcarpal joints

A

True

47
Q

How many degrees of freedom does the midcarpal joint have

A

2

48
Q

What 2 motions does the midcarpal joint contribute to most

A

Extension and radial deviation

49
Q

True or False:

The intercarpal joints allow minimal movement to accomodate hand and wrist positioning

A

True

50
Q

Which side of the intercarpal joints is more mobile

A

Ulnar side

51
Q

What ligaments of the intercarpal joints are stronger palmar or dorsal ligaments

A

Palmar ligaments

52
Q

True or False:

The palmar side of the lunate is reltively unstable

A

True

53
Q

Which carpal is the most commonly dislocated

A

Lunate

54
Q

Does the scaphoid have any ligament attachment dorsally near the proximal pole

A

No

55
Q

What does the lack of ligament attachment on the proximal pole of the scaphoid potentially lead to

A

Ganglion cyst formation

56
Q

True or False:

Ligaments are support structures and passive movers

A

True

57
Q

What does the dorsal radiocarpal ligament contact

A

Lunate and radius

58
Q

What is the dorsal radiocarpal ligament a check rein to

A

End range wrist flexion

59
Q

What are the ulnar and radial collateral ligaments check reins to

A

Radial: Ulnar deviation
Ulnar: Radial deviation

60
Q

True or False:

The volar radiocarpal ligament is the most important of all ligaments for stability and passive mobility contribution

A

True

61
Q

How many bands does the volar radiocarpal ligament have

A

3

62
Q

What is the coupled motion with flexion

A

Ulnar deviation

63
Q

What is the coupled motion with extension

A

Radial deviation

64
Q

What is the angle of the radial head called

A

Ulnar tilt

65
Q

What is the angle of the radial head

A

25

66
Q

During flexion at the radiocarpal joint what arthrokinematics occur

A

Palmar roll and dorsal glide

67
Q

During extension at the radiocarpal joint what arthrokinematics occur

A

Dorsal roll and palmar glide

68
Q

During radial deviation at the radiocarpal joint what arthrokinematics occur

A

Radial roll and ulnar glide

69
Q

During ulnar deviation at the radiocarpal joint what arthrokinematics occur

A

Ulnar roll and radial glide

70
Q

When do the palmar and intercarpal ligaments become taut

A

Full extension

71
Q

What is the closed pack position of the radiocarpal joint

A

Full extension

72
Q

For the intercalated segment what counter rotation occurs during flexion

A

The scaphoid flexes and the lunate and triquetrium extend

73
Q

What does counter rotation result in

A

Increased ligamentous tension

74
Q

Is the counter rotation noticeable

A

No

75
Q

Increasing coaptation of the midcarpal articular surfaces does what

A

Increases stability

76
Q

For intercalated segment what counter rotation occurs during extension

A

The scaphoid extends and the lunate and triquetrium flex

77
Q

What are the 2 halves of the midcarpal joint

A

Ulnar and radial

78
Q

What is the arthrokinematic configuration of the ulnar side of the midcarpal joint

A

Convex on concave in frontal and sagittal planes

79
Q

What bones are in contact at the ulnar side of the midcarpal joint

A

Hamate and capitate on lunate and triquetrium

80
Q

What is the arthrokinematic configuration of the radial side of the midcarpal joint

A

Concave on convex in frontal and sagittal planes

81
Q

What bones are in contact at the radial side of the midcarpal joint

A

Trapezoid and trapezium on the scaphoid

82
Q

What is the ulnar side of the midcarpal joint linked anatomically and functionally with

A

Radiocarpal joint

83
Q

Why is the ulnar side of the midcarpal joint linked to the radiocarpal joint

A

Due to the same convex on concave orientation

84
Q

What are the arthrokinematic motions for flexion and extension at the ulnar side of the metacarpal joint

A

Flexion: Palmar roll and dorsal glide
Extension: Dorsal roll and palmar glide

85
Q

What is the radial side of the midcarpal joint linked anatomically with

A

Radiocarpal joint

86
Q

Is the radial side of the midcarpal joint linked functionally with the radiocarpal joint

A

No

87
Q

What are the arthrokinematic motions for flexion and extension of the radial side of the metacarpal joint

A

Flexion: Palmar roll and glide
Extension: Dorsal roll and glide

88
Q

During radial deviation which way do the distal row of carpals move

A

Toward the radial deviation with the proximal row

89
Q

What happens when the ligaments and bones create limitation and approximation during radial deviation

A

The scaphoid and lunate move palmarly and the trapezoid and trapezium move dorsally

90
Q

What does the motion of the scaphoid, lunate, trapezoid, and trapezium allow for

A

Full ROM

91
Q

What is the closed pack postion of the radiocarpal and midcarpal joint

A

Full radial deviation

92
Q

During ulnar deviation which way does the distal row of carpals move

A

Toward the ulnar deviation with the proximal row of carpals

93
Q

What happens when the ligaments and bones create limitation and approximation during ulnar deviation

A

The scaphoid and lunate move dorsally and the trapezoid and trapezium move palmarly

94
Q

What does the motion of the scaphoid, lunate, trapezoid, and trapezium allow for

A

Full ROM

95
Q

What is the closed pack position of the wrist complex

A

45 wrist extension and slight radial deviation

96
Q

What occurs during extension to the carpals

A

Rotation toward supination which tightens the ligaments and draws the carpals together

97
Q

What is the open pack position of the wrist complex

A

Slight flexion with slight ulnar deviation

98
Q

What are the primary wrist flexors (3)

A
  1. Palmaris longus
  2. Flexor carpi radialis
  3. Flexor carpi ulnaris
99
Q

Which muscle is a better secondary deviator the flexor carpi radialis or flexor carpi ulnaris

A

Flexor carpi ulnaris

100
Q

Why is the flexor carpi ulnaris a better secondary deviator

A

Due to the proximal insertion

101
Q

What type of muscle is the flexor carpi ulnaris

A

Spurt

102
Q

What are the digit flexors with secondary wrist action (3)

A
  1. Flexor digitorum supericialis
  2. Flexor digitorum profundas
  3. Flexor pollicis longus
103
Q

Which muscle is better able to function as a wrist flexor flexor digitorum superficialis or flexor digitorum profundas

A

Flexor digitorum superficialis

104
Q

Why is the flexor digitorum superficialis a better wrist flexor

A

It inserts closer to the wrist

105
Q

What are the primary extensors of the wrist (3)

A
  1. ECRL
  2. ECRB
  3. ECU
106
Q

Which is more effective at wrist flexion and why, ECRL or ECRB

A

ECRB due to its central attachment to metacarpal 3

107
Q

What are the digit extensors with secondary wrist action (6)

A
  1. ED
  2. EI
  3. EDM
  4. EPL
  5. EPB
  6. APL
108
Q

What muscles are injured during dequarvains tenosynovitis (2)

A
  1. APL

2. EPB

109
Q

True or False:
Wrist deviation contribution detracts from primary action of the thumb so requires synergistic activity of ECU to offset it

A

True

110
Q

How do the ECRL/ECRB work synergistically with the ED

A

If the ECRL/ECRB is weak the ED will help with extension of the wrist

111
Q

How can you tell if the ED is aiding the ECRL/ECRB with wrist extension

A

Extension of the fingers

112
Q

Where does the ADM originate from

A

Pisiform

113
Q

How do the FCU and ADM work synergistically

A

FCU contraction stabilizes pisiform to allow abduction of 5th digit

114
Q

How dot he ECU and EPL/EPB work synergistically during thumb extension

A

ECU maintains the hand in neutral position

115
Q

What happens to the fingers when you extend the wrist

A

Finger flexion

116
Q

What happens to the fingers when you flex the wrist

A

Finger extension

117
Q

What does the corresponding motion at the fingers during wrist motion minimize

A

Active and passive insufficiency

118
Q

What is tenodesis

A

Benefits from tightness for function

119
Q

With minimal active wrist extension what happens to the finger flexors

A

Adaptive shortening

120
Q

For paraplegics increased passive tenison in the fingers allows for what

A

Increased ADL function

121
Q

How do the FCU and ECU work synergistically (3)

A
  1. Pure ulnar deviation
  2. Flexion and ulnar deviation
  3. Extension and ulnar deviation
122
Q

When do the FCU and ECU cause pure ulnar deviation

A

Equal force output of both muscles

123
Q

When do the FCU and ECU cause flexion and ulnar deviation

A

FCU force greater than ECU

124
Q

When do the FCU and ECU cause extension and ulnar deviation

A

ECU force greater than FCU

125
Q

How do the FCR and ECR act synergistically

A

Same as FCU and ECU but to the radial side

126
Q

What type of joint is the CMC 2-4

A

Plane synovial

127
Q

What is all of the arthrokinematic orientations of the digit joints except the 1st CMC

A

Concave on convex

128
Q

What type of joint is the 5th CMC

A

Condyoid/saddle

129
Q

What motions occur at the 5th CMC

A

Flexion/extension and ABD/ADD

130
Q

What does the 5th CMC being a saddle joint contribute to

A

Opposition

131
Q

What type of joint is the 1st CMC

A

Saddle

132
Q

What are the articulating surfaces of the 1st CMC

A

Trapezium and 1st metacarpal

133
Q

What is the arthrokinematic orientation of the 1st CMC joint in the sagittal plane (ABD/ADD)

A

Convex on concave

134
Q

What is the arthrokinematic orientation of the 1st CMC joint in the frontal plane (Flex/Ext)

A

Concave on convex

135
Q

True or False:

Ligament and capsular laxity allows some rotation and wide ROM at the 1st CMC joint

A

True

136
Q

What is the amount of flex, ext, and abd at the 1st CMC joint

A

Flex: 15-20
Ext: 20-30
Abd: 70

137
Q

What plane and axis goes with ABD/ADD of 1st CMC

A

Sagittal plane M-L axis

138
Q

What plane and axis goer with Flex/Ext of 1st CMC

A

Frontal plane A-P axis

139
Q

What is the arthrokinematic motion at the CMC 2-5 during flexion and extension

A

Flexion: Anterior roll and glide
Extension: Posterior roll and glide

140
Q

What is the arthokinematic motion at the 1st CMC during flexion and extension

A

Extension: Lateral/Radial roll and glide
Flexion: Medial/Ulnar roll and glide

141
Q

What is the arthrokinematic motion at the 1st CMC during ABD and ADD

A

ABD: Anterior roll posterior glide
ADD: Posterior roll anterior glide

142
Q

What type of joint are the 2-5 MCP joints

A

Condyloid

143
Q

When are the collateral ligaments and capsule taut for the MCP joints

A

Flexion

144
Q

What is the close pack position of the MCP 2-5

A

Flexion

145
Q

True or False:

ABD/ADD at the 2-5 MCP is difficult while flexed

A

True

146
Q

What is the open pack of the 2-5 MCP

A

Neutral to slight flexion

147
Q

What happens to flexion as you go from radial side of the hand to the ulnar side of the hand

A

Increases from 90 to 110

148
Q

What is extension of the 2-5 MCP active and passive

A

Active: 30-40
Passive: over 90

149
Q

What is ABD/ADD ROM at 2-5 MCP

A

30-40

150
Q

When does ABD/ADD increase

A

With extension

151
Q

What type of joint is the 1st MCP joint

A

Condyloid

152
Q

What do the 1st CMC and 1st MCP work synergistically to allow

A

5 degrees of freedom for opposition

153
Q

What type of joint are the PIP and DIP joints

A

Hinge

154
Q

Does ROM increase or decrease from IP joint 1 to 5

A

Increase

155
Q

What is flexion at the 1st PIP and DIP

A

PIP: 100-110
DIP: 80

156
Q

What is flexion at the 5th PIP and DIP

A

PIP: 135
DIP: 90

157
Q

What is a power grip

A

Used when there is stability or large forces are required without the need for precision

158
Q

What shape are the objects for power grip

A

Spherical or cylindrical

159
Q

What is a precision grip

A

Contour to object and/or some delicate action needed

160
Q

What is a power (key) pinch

A

Holding object between thumb and lateral border of index finger requires large forces to stabilize object

161
Q

What is a precision pinch

A

Fine control between index and thumb without power

162
Q

What are the 2 types of pinches

A

Pulp to pulp and tip to tip

163
Q

What is a hook grip

A

Doesn’t require thumb only partial flexion of PIPs and DIPS static nature grip for long periods of time

164
Q

What is the main muscle for a hook grip

A

Flexor digitorum profundas

165
Q

What causes swan-neck deformity

A

RA causing decrease of ligament integrity and increased flexor pull on MCP joint

166
Q

What is the result of swan-neck deformity

A

MCP flexion, PIP extension, DIP flexion

167
Q

What is the result of boutonniere deformity

A

MCP extension, PIP flexion, DIP extension

168
Q

Do people with RA usually have ulnar or radial drift

A

Ulnar drift due to more mobility and looser on ulnar side (path of least resistance)

169
Q

What is the rest position of the hand

A
Wrist extension: 20
Ulnar deviation: 10
MCP flexion: 45
PIP flexion: 30
DIP: slight flexion
170
Q

What does the resting position of the hand optimize

A

Finger flexor force via optimal length tension

171
Q

True or False:

In the resting hand position all of the wrist muscles are under equal tension

A

True

172
Q

What is the immobilization position for the hand

A

Wrist extension: less than 20
MCP flexion: 70
IP joints: neutral
Thumb: CMC wide ABD, MCP slight flexion, and IP neutral

173
Q

Why is the hand immobilized like this

A

To minimize potential for contractures or adaptive shortening

174
Q

Motivation

A

Mike Elhers likes little boyz!