Test 2 Flashcards
(203 cards)
0
Q
SCJ anterior/posterior ligaments do what?
A
Check ant/post translation
1
Q
7 joint involved in shoulder elevation
A
AC GH SC ST thoracic spine Costotransverse/ costovertebral Costochondral
2
Q
SCJ interclavicular ligaments do what?
A
Checks clavicular depression
3
Q
SCJ costoclavicular ligament
A
Anterior and posterior fibers
Limits elevation
Contributes to inferior gliding of clavicle
4
Q
SCJ type of joint
A
Saddle shape, plane synovial
5
Q
SCJ frontal plane
A
Frontal plane- convex on concave
Elevation and depression
6
Q
SCJ elevation
A
48 degrees
7
Q
SCJ depression
A
10 degrees
- you don’t depress often
8
Q
SCJ in transverse plane
A
Concave on convex
Protraction
Retraction
9
Q
SCJ protraction
A
20 degrees
10
Q
SCJ retraction
A
30 degrees
11
Q
SCJ in sagittal plane
A
Saddle shape
Posterior rotation
Anterior rotation
12
Q
SCJ posterior rotation
A
50 degrees
13
Q
SCJ anterior rotation
A
<10 degrees
14
Q
ACJ joint
A
Capsule is weak
Superior and inferior ligaments
Superior checks distal clavicle from moving posteriorly
15
Q
ACJ coracoclavicular ligament- Conoid
A
- resist distal clavicular superior motion
- limit upward rotation of scapula
- posteriorly rotates clavicle
16
Q
ACJ coracoclavicular- trapezoid
A
Limit posterior displacement of clavicle
Limits upward rotation of scapula
Posteriorly rotates clavicle
17
Q
ACJ coracoacromial ligament
A
Roof for GHJ
protects subacromial bursa and RTC
18
Q
What kind of joint is the ACJ
A
Planar
19
Q
Movement of ACJ
A
Minimal
20-40 degrees anterior/posterior tilting
30 degrees upward/downward rotation
30 degrees IR/ER
20
Q
Scapulothoracic joint positioning
A
30-45 degrees coronal plane
10-15 degrees anteriorly tilting
10 degrees upwardly rotated
21
Q
Scapulothoracic joint upward rotation mobility
A
60 degrees
Axillary line
- coupled with posterior rotation SCJ
Coupled with clavicular elevation
22
Q
Scapulothoracic joint elevation and depression occurs where
A
At SCJ
23
Q
Scapulothoracic joint protraction retraction occurs where
A
At SCJ
24
Scapulothoracic joint IR/ER and anterior/posterior tilting occurs where
At ACJ
25
Scapulo-humeral rhythm
- maintain optimal alignment of the glenoid and humeral head
- increase ROM available in elevation
- maintain optimal length-tension relationship for the scapulo-humeral muscles
- -> minimize activity insufficiency
26
What effect does gravity have on GHJ
Fall-out
27
What prevents subluxation of GHJ
Labrum
Joint capsule acts as suction
RTC
amongst others
28
Labrum does what to GHJ
Increases depth by 50%
29
GHJ capsule
Loose anteriorly and inferiority
Tight superiorly
Creates intrarticular pressure
30
Superior GH ligament
1) labrum to humerus connects with coracohumeral ligament
| 2) anterior and inferior stability
31
Middle GH ligament
- superior anterior labrum to anterior humerus
| - anterior joint stability up to 60 degrees abduction
32
Inferior GH ligament
- 45 degrees abduction resists inferior translation
- ER resists anterior translation
- IR resists posterior translation
33
GHJ coracohumeral ligament
Limits inferior translation
34
Humeral head orientation
Medially
Superiorly: 130-150 degrees
Posteriorly: 30 degrees
35
GHJ mobility
Convex on concave
36
Describe the GHJ motions that occur with abduction
External rotation
37
GHJ motions that occur with scapular plane
Less ER
38
GHJ motion that occurs with flexion
Internal rotation
39
Scapulo humeral rhythm movements of humerus and scapula
Elevation of the humerus
Upward rotation and posterior tilting of scapula
2:1 ratio (GHJ:STJ)
40
4 joints getting to 180 degrees
SCJ-40 elevation and upward rotation
ACJ- minimal motion
STJ- 60 degrees upward rotation
GHJ- 120 degrees elevation
41
How many muscles act on the shoulder during elevation?
```
18
Biceps
Triceps
Deltoid x3
Traps x3
SITS
rhomboids x2
Levator scapulae
Serrated anterior
Lats
Teres major
```
42
Upward scapular rotators
Upper trapezius
Middle trapezius
Lower trapezius
Serratus anterior- prime mover
43
Compression and joint stabilization muscles of shoulder
Infraspinatus
Teres minor
Subscapularis
Supraspinatus- some elevation too
44
angle of pull causes what on humerus?
Compression and spin
45
Glenohumeral elevation
- Supraspinatus: test in scapular plane. Most active 0-60 degrees abduction, scapula starts moving at 60
- Deltoid: prime elevator for flexion, assist abduction after 15 degrees. More superior force
46
Supraspinatus lever arm
Much better lever arm than deltoid, larger axis of rotation so get more force
Deltoid turns off up top because moment arm is smaller because of active insufficiency
47
Deltoid and Supraspinatus during arm elevation
Deltoid has poor ma during early elevation
Supraspinatus has longer ma during elevation
Deltoid ma improves in mid-range
Deltoid provides greater abduction force than Supraspinatus
48
Deltoid and rotator cuff during arm elevation
Deltoid causes superior glide of humerus- impingement
| Cuff causes inferior glided
49
Shoulder depression muscles in weight bearing
Latissimus Doris
Pectoral is major
- need to work because they are counteracting upper trap. Ys Ts Ws
50
What muscle prevents scapular internal rotation
Rhomboids
- serratus anterior does the IR of scapula
51
Teres major and internal rotation
Extends humerus, if teres major is activated without the rhomboids, scapula would internally rotate
52
Shoulder muscles for scapular depression and abduction
Pec minor
53
GIRD
Glenohumeral IR deficit
-a loss of IR of 20 degrees or more compared to contralateral side
Seen primarily in baseball athletes and overhead throwing. Huge difference in dominant vs. non dominant hand
54
Factors in shoulder overuse injuries
Impingement
RTC tears
SLAP tears
55
Causes of GIRD
Humeral retroversion (so sits more posterior in GHJ)
Throwing causes ER torque
Humeral head sits posteriorly on glenoid
56
GIRD measurements
```
Total motion
ER + IR= total motion
>5 degree loss in total motion
Increase risk of injury
Greater number of lost games
```
57
Causes of serratus anterior weakness
Long thoracic nerve palsy
| Disuse
58
Scapular winging in flexion
Because serratus anterior is not holding scapula
- could be because pec minor internally rotates the scapula from the front and if it's stronger than the serratus then winging will occur
59
Causes of upper trap weakness
```
Spinal accessory nerve palsy (SNAP)
Positives scapular flip
Trapezius atrophy
Depressed scapula
Trap weakness
Limited shoulder abduction
```
60
Patient has weakness in shoulder flexion, which muscle is it?
Serratus anterior
61
Serratus anterior vs. trapezius weakness
Winging vs. flipping out
62
Upper trapezius weakness
Cannot abduct
Downwardly rotate and scapula flips out
Check medial border of scapula to see the downward rotation
63
Upper trapezius overuse
Decrease upward rotation of scapula
| Increase shoulder impingement
64
Causes of rotator cuff weakness
```
Overuse
Surgery
Disuse
Injury
C5 rediculopathy
```
65
Rotator cuff weakness signs
Shoulder hike, cannot ER so cannot abduct
67
To abduct the arm you must:
Externally rotate the arm
68
Shoulder subluxation
no deltoid or RC
upper trap atrophy
posture is #1
69
How can we improve shoulder subluxation
muscle strength
posture
upper trap
RC muscles
70
The elbow complex
- designed to improve mobility for the hand in space
- provide stability for the hand during forceful movements
- consists of elbow joint (humeroulnar or humeroradial) and proximal and distal radioulnar joints
71
The elbow joint
- compound joint; modified or loose hinge joint
| - functions as a modified or loose hinge joint
72
how many degrees of freedom is the elbow joint
1 degree of freedom
- flexion and extension in the sagittal plane
- slight axial rotation and side to side motion of the ulna during flexion and extension: therefore a modified or loose hinge joint
73
In what position is the elbow joint close packed?
- extension
74
close packed position
bones and ligaments and position of least mobility
75
open packed position
bones and ligaments are in most mobile position
| - The more swelling in a capsule, the more you want the joint to be in open packed position
76
What kind of joint is the radius when attached to the humerus?
spin joint so we can pronate and supinate
77
Elbow in flexion
- has a larger surface area to provide joint surfaces and more stability in weight bearing
78
Elbow joint capsule
- single joint capsule for 3 joints
- capsule fairly loose and weak anteriorly and posteriorly
- Reinforced with ligaments medially and laterally
- in flexion and extension bone sits really well but not side to side
79
most common side for baseball injury in the elbow
medially
80
elbow joint medial ligaments
- flexors on medial side to stabilize
- proximal MCL fused with common flexor tendon
- limits extension at end range
- guides joint motion throughout flexion
- provides some resistance to longitudinal distraction
- pronation
- Main restraint 20-120 degrees; not 20-0 because bony component takes over
81
primary restraint of valgus stress on elbow
anterior MCL at 20-120 degrees of elbow flexion
82
valgus stress test
put elbow in valgus by moving forearm laterally
get more joint play MCL; wrist flexors resist
in 30 degrees flexion
A lot of motion damages the ligaments
83
varus stress test
move forearm medial, test LCL
wrist extensors resist
in 30 degrees flexion
A lot of motion damages ligaments
84
Elbow joint lateral ligaments
- LCL fused with common extensor tendon
- stabilizes against varus stress and combined varus and supination stress
- reinforces humeroradial joint
- stabilizes radial head
- secure ulna to humerus
85
Muscles on anterior aspect of the elbow: flexors
```
brachialis
biceps brachii
brachioradialis
supinator teres
pronator teres
flexor carpi radialis
flexor carpi ulnaris
flexor digitorum superficialis
palmaris longus
```
86
muscles on posterior aspect of elbow: extensors
```
triceps brachii
anconeus
supinator teres
pronator teres
extensor carpi radialis longus
extensor carpi radialis brevis
extensor carpi ulnaris
extensor digitorum communis
extensor digiti minimi
```
87
Elbow joint:
| function- axis of motion
slight angle; not as fixed as previously thought
AoR is important so you know joint movement and angles by which they move.
Want to do ROM in the direction it should be done
88
Carrying angle
- cubitus valgus
- in anatomical position
- caused by configuration of articulating surfaces
- normal 10-15 degrees
- females> males
- at 30 degrees of flexion, the carrying angle disappears
- benefit is you can carry heavy things without hitting the legs
89
More PROM of the elbow because
of assistance, don't activate biceps and soft issue approximation won't stop you so soon
90
The amount of range of motion available at the elbow depends on
- type of motion (active or passive): AROM flexion 135-145 degrees, PROM flexion 150-160
- Position of forearm (supination and pronation): if arm pronated earlier, stop because radius is over ulna
- BMI
- position of shoulder (2 joint muscle): i.e triceps
- Swelling: stays within capsule
91
Capsule
- holds joints together
- lubricates inner layer
- holds fluid in joint
- crucial
- stretched ballon can be manipulated, if swollen capsule is distended and can't be moved
- -> in open packed, won't get full ROM
92
Elbow joint 2 functions
stability
mobility
muscle action
93
elbow joint stability
- full ext: close packed
- bony contacts
- MCL prevents valgus stress/force
- LCL prevents varus stress/force
- The joint capsule's ability to prevent varus and valgus stress depends on elbow position: better in full extension
- open packed: less stability from capsule, greater stability from ligaments
- Co- contraction of flexor and extensor muscles of the wrist and elbow help to provide stability
94
Elbow joint: brachialis
- flexor- use most
- one joint muscle
- A mobility muscle: allow for movement
- 3rd class lever; mechanically insufficient in concentric contraction
- large physiological cross sectional area (PCSA)
- moment arm greatest at 100 degrees flexion
- unaffected by forearm position because attaches to ulna
- active during all types of contractions and speeds
95
Elbow joint: biceps brachii
- flexor
- 2 joint muscle
- a mobility muscle
- long head has the largest volume amongst the flexors (can get big)
- relatively small PCSA
- M.A is greatest between 80-100 degrees flexion
- affected by shoulder and forearm position: helps in supination
- activation depend on forearm position and magnitude of resistance
- in pure pronation, can't produce most power because it supinate
96
When flexing you start with which muscle
brachialis
| if need alot of force--> biceps brachii
97
Why do you sometimes get shoulder extension when carrying stuff?
because if bending and not at optimal length tension, won't produce enough force
98
elbow joint: brachioradialis
- flexor
- 1 joint muscle
- compression: ALOT
- small PCSA
- M.A greatest at 100-120 degrees of flexion
- Affected by forearm positions an types of contractions; contracting have more stability
- helps stabilize the joint
99
Elbow joint: triceps brachii
- extensor
- 2 joint muscle and 1 joint muscle
- small PCSA
- maximum isometric torque produced at 90 degrees of flexion
- not affect by forearm positions: attaches right to olecranon
- synergist during supination when biceps brachii is active
100
Why are the triceps a synergist during supination when biceps are active
because when you need a lot of force to supinate when use biceps you get supination and flexion. Triceps will limit that flexion
101
Proximal radioulnar joint
uniaxial pivot joint
annular ligament- rotates
Quadrate ligament- stays in position
102
distal radioulnar joint
interosseous membrane
| dorsal and palmar radioulnar ligaments
103
what does interosseous membrane do?
helps transfer force through ulna
from radius to ulna
increased risk of damage when you condense force to small area
104
Radioulnar joint range of motion
- longitudinal axis
- total of 150 degrees ROM
- measure at 90 degrees of elbow flexion to distinguish between radioulnar joint motion and shoulder rotation
105
pronation of radioulnar joint limited by
bony approximation
tension dorsal radioulnar ligament
posterior fibers of MCL in elbow
At extension, may be tension in biceps
106
supination of radioulnar joint limited by
passive tension of palmar radioulnar ligament and oblique cord
107
Radioulnar joint supination
supinator always active and biceps when increasing the force
108
radioulnar joint pronation
pronator quadratus always active, pronator teres always flex elbow
109
Function of elbow complex
- to accomplish most simple tasks
- -> 30-130 degrees of flexion
- -> 50 degrees of pronation to 50 degrees of supination
Use telephone: requires large arc flexion and sup/pro
110
elbow complex relationship to hand and wrist
- radioulnar joint provides mobility to the hand but then sacrifice stability
- The forearm is therefore not a stable base for attachment of hand and wrist muscles
- Many of those muscles therefore attach to distal end of humerus
- These muscles provide stability (compression) to the elbow joint
* wrist muscles not really affected by forearm position
111
Elbow complex and age
- decreased muscle strength with increased age
| - elderly also more severe errors in judgement about the amount of effort needed to accomplish motor task
112
Injuries to elbow complex
- injuries fairly common
- compression injuries (bony contact)
- bony failure when landing on extended elbow. forcing bone together will crack
113
Forceful muscle contraction injuries in the elbow
- high compression- such as in baseball
- nerve compression (ulnar nerve compressed n the cubital tunnel by flexor carpi ulnaris)
- cubital tunnel syndrome
- more contraction, more compression, jam cartilage which doesn't heal if damaged
114
Distraction injuries in the elbow
- radial head pulled out of the annular ligament in elbow extension and pronation
115
varus and valgus injuries in the elbow
- distraction medially will cause compression laterally
| - avascular necrosis of compressed surface (capitulum of radial head)
116
medial epicondylitis or tendinopathy
golfers elbow
117
lateral epicondylities or tendinopathy
tennis elbow
118
2 joints of wrist
Radiocarpal
| Midcarpal
119
What is good about having 2 joints at the wrist
Larger ROM with less articular surface exposed
| Flatter joint surfaces that can tolerate more pressure
120
Wrist circumduction is a combo of what
Flexion
Extension
Radial and ulnar deviation
121
Wrist flexion normal range
65-85
122
Wrist extension normal range
60-85
123
Wrist radial deviation normal value
15-21
124
Wrist ulnar deviation normal value
20-45
125
Proximal segment of Radiocarpal joint
Concave
| Radius and radioulnar disc
126
Distal segment of radiocarpal joint
Convex
| Scaphoid, lunate, triquetrium
127
How much is the proximal radiocarpal joint angled
Volarly 11 degrees
| Ulnarly 23 degrees
128
Why is the proximal radiocarpal joint incongruent
Contact surface between 20-40% of the surfaces
129
Proximal radiocarpal joint allows for which movements
Flex>ext
| Ulnar deviation >radial deviation
130
Compression in wrist
80%of load in scaphoid, lunate ( 60% contact with scaphoid, and 40% lunate)
TFCC: 20%
131
Why is having an ulna the same length as the radius bad?
Ulnar positive variance: more weight bearing in ulna!
132
FOOSH
Fall on outstretched hand
- dorsal displacement of ulna
- fracture of distal radius
- most common is colles
- in pronation and dorsiflexion
133
Proximal midcarpal joint
Scaphoid
Lunate
Triquetrium
134
Distal midcarpal joint
Trapezium
Trapezoid
Capitate
Hamate
135
Extrinsic wrist ligaments
Connect carpals to radius and ulna
| Weaker but better potential for healing
136
Intrinsic wrist ligaments
Interconnect the carpals
Stronger but have to rely on synovial fluid for nutrition
- no bld flow for nutrition
137
Wrist flexion and extension
```
Complex and varied
Difficulty determining where AoR is
- affects goniometry
Closed packed in extension
1st capitate moves, then scaphoid, then lunate
```
138
Why is closed packed wrist extension good?
That is how we weight bear
139
Wrist radial and ulnar deviation
Complex and varied
| Full radial deviation is closed packed position for radiocarpal and midcarpal joints
140
How much wrist motion do ADLs requiring the hand need?
Minimal requirements
10 degrees flexion, 35 degrees extension (so flexors are in optimal to grip)
54 degrees flex, 60 degrees ext, 40 degrees UD,17 degrees RD
Consensus is that wrist extension and ulnar deviation is most important
For fusion: use 20 degrees extension and 10 degrees UD
141
Primary role of wrist muscles
- Provide stable base for hand
- while adjusting position to achieve optimal length tension relationship in the long finger muscles
*if wrist injury and cannot bend, may accommodate with a wider grip so they can hold things
142
Primary volar wrist muscles
Palmaris longus
Flexor carpi radialis
Flexor carpi ulnaris
143
Which volar muscles work together during flexion to avoid deviation?
FCU
| FCR
144
In what percentage of people is the palmaris longus absent?
14%
145
How is the moment arm increased in the volar side of the wrist?
FCU envelopes the pisiform
| Pisiform sits on the triquetrium
146
If you have carpal tunnel what is cut to correct it?
Flexor retinaculum
147
Primary dorsal wrist muscles
Extensor carpi ulnaris
Extensor carpi radialis longus
Extensor carpi radialis brevis
148
What muscles work together during wrist extension to avoid deviation
ECU
ECRL
ECRB
149
How is the extensor carpi ulnaris affected by forearm position?
Decreased moment arm in pronation
| In supination, you extend and ulnarly deviate which is when the wrist is strong
150
Which muscles pair in wrist flexion
FCR
| FCU
151
Which muscles pair in wrist extension
ECRL
ECRB
ECU
152
Which muscles pair in wrist radial deviation
FCR
ECRL
ECRB
153
Which muscles pair in ulnar deviation
ECU
| FCU
154
The carpal tunnel
- Proximal transverse arch- persists even when hand fully opened
- transverse carpal ligament between the hook of hamate/ pisiform, and scaphoid/ trapezium
- contains median nerve, and extrinsic flexor tendons
155
Where the transverse carpal ligament span?
Between hook of hamate/ pisiform
| Between scaphoid/ trapezium
156
Carpal tunnel syndrome
Long term median nerve compression can lead to atrophy of the median nerve innervated by muscles in the thenar eminence
- "ape hand"
- cannot get full opposition
157
Joints of the hand
CMC
MCP
PIP
DIP
158
How many bones are in the hand
19
159
How many joints are in the hand distal to the carpals?
19
160
CMC of the finger
- Distal carpal row and bases of metacarpals
- 2nd and 3rd have minimal mobility; provide stable base
- 4th has perceptible flex/ext
- 5th has 2 df; flex/ext, add/abd
161
MCP Joint of the hand
- convex metacarpal
- concave base of phalanx
- condyloid with 2df; flex/ext, abd/add
- metacarpal head has 180 degrees of articular surface, mainly volarly
- phalanx has 20 degrees of articulating surface
- less articulating surface in frontal plane
- cannot abduct/ addict MCP when flexed
162
MCP of fingers
- capsule lax in extension
- 2 collateral ligaments
- volar plate enhances stability; in ext protects joint surface
- protects articulating surface
- blend with deep transverse metacarpal ligaments
163
What keeps FDP and FDS close to the bone?
Pulleys
| - bones aren't very close together in order to have movement
164
Closed packed position of MCP joints of finger
Full flexion
| Collateral ligaments taut
165
How does flexion of the MCP joints of the finger increase?
Radially to ulnarly
- index finger: 90 degrees flexion
- little finger: 110 degrees flexion
166
How does hyper extension of MCP joint vary between fingers?
It doesn't, it's the same between fingers
| Varies among individuals
167
When is abd/add of the MCP joints at a max?
At full extension
168
IP joints of fingers
- true synovial hinge
- 1df; flex/ ext with very little hyperextension
- proximal joint surface has 2 shallow concave facets with a central ridge
169
PIP flexion vs DIP flexion, which is more
PIP
170
Which PIP and DIP have the greatest ROM?
Increased ROM achieved ulnarly
| 5th DIP and PIP have the most
171
IP joints of fingers favor angulation toward which bone?
Scaphoid- facilitates opposition of fingers with thumb
172
Anti-deformity positioning of the hand
- immobilization in a position that will minimize contractures
- MCP flexion
- IP joints more in extension
- thumb in CMC abduction
*open packed position so that tissues are not stretched and won't cause a contracture
173
Extrinsic finger flexors
FDS
FDP
* both muscles dependent on wrist position for optimal length tension relationship
174
FDS
- attaches proximal to DIP joint
- flex PIP joint
- assist in MCP flexion
- greater moment arm at the MCP but lesser at PIP
- used when greater force necessary or during wrist flexion ( with active insufficiency of FDP)
175
FDP
- flexes DIP,PIP, and MCP
| - primary muscles with gentle pinch
176
When FDS is not present, what happens when you forcefully press the thumb and finger tip together?
Produces DIP flexion with PIP extension
| FDP not able to flex both joints
177
Finger flexion grip
- pistol grip
- wider ulnarly
- longer flexors of digits 4-5 will not have to flex as much which minimizes loss of tension
- not a concern with light grip then shape accommodates the greater flexion range
178
Mechanisms of finger flexors
- long tendons of finger flexors needs to glide smoothly and stay close to hand
- flexor retinaculum
- bursae
- digital tendon sheet
179
Extrinsic finger extensors
Extensor digitorum
Extensor indicis
Extensor digiti minimi
- only muscles able to perform MCP extension
- also perform wrist extension
180
What does the extensor digitorum tendon split into
Central tendon
| Lateral bands distal to PIP
181
Extensor mechanism
- ED passes dorsal to MCP joint axis
- ED contracts
- tension on extensor hood cause MCP joint extension
- PIP and DIP flexion due to passive tension in FDS and FDP
- need intrinsic muscle assistance to also achieve DIP and PIP ext
182
Intrinsic finger musclse
Dorsal and Volar interossei
| Lumbricals
183
Dorsal and Volar interossei
- Arise from between metacarpals
- Attach to the extensor hood and lateral bands
- Important for extensor mechanism
- Just volar to the MCP joint axis
- Compress MCP joint when in extension- helps prevent clawing (MCP hyperextension)
- Performs finger add/abd of fingers when MCP in ext
184
Dorsal and Volar interossei have a greater moment arm when?
- In MCP joint flexion greater moment arm and therefore produce greater flexion torque at MCP
185
Where do the dorsal and volar interossei attach
to central tendon and lateral bands and therefore produces DIP and PIP extension (together)
186
When are interossei consistently active
with MCP flexion
| with PIP and DIP extension
187
Lumbricals
- attaches at both ends to tendons of other muscles; so not pulling on bone.
- FDP and lateral bands of the extensor mechanism
- Contraction causes PIP and DIP extension while decreasing tension in FDP tendon (decreased passive flexion force)
- IP extensors regardless of MCP joint position
- Hood helps with extension by decreasing resistance
188
Loss of intrinsic: Clawing
splint to keep MCP in flexion so that the EDC can cause PIP and DIP extension without the intrinsic muscles
- the flexor tendon not as tight, still get pull
189
If fingers are hypermobile then what happens?
able to hyperextend the PIP and then able to only flex DIP
190
Intrinsic plus position of fingers
looks like holding wood with lumbricals
191
intrinsic minus position of fingers
look like claw, can't use intrinsic muscles
192
Boutonniere deformity
ruptured central tendon
| finger stuck up and curved
193
SWan's neck deformity
DIP look curved up like neck
| hyperextend PIP
194
Thumb CMC
trapeziometacarpal joint
- saddle joint
- 2 df
- flex/ext and add/abd
- can perform opposition: tip of thumb can oppose tip of fingers
- Capsule relative lax but reinforced with ligaments
- can't hold cup without ligaments
195
Thumb MCP
condyloid joint
2 df
less ROM compared to fingers
sesamoid bones on volar surface increase m.a
196
thumb IP
identical to the fingers IP joints
197
extrinsic thumb muscles
```
FPL flexor and located volarly
EPB, EPL, APL are dorsally
EPL attaches to base of distal phalanx
EPB attaches to proximal phalanx
APL attaches to base of metacarpal
since multi joint- affected by wrist position
```
198
Intrinsic thumb muscles
- five thenar muscles
- OP, APB, FPB, AP, 1st dorsal interossei
- 1st dorsal interossi is bipennate arising from metacarpal 1 and 2
199
Power grip
full hand prehension
200
Precision handling
finger thumb prehension
201
Power grip- grasps (4)
cylindrical
spherical
hook grip
lateral prehension: abd/add
202
precision handling- pinch
pad to pad: do not need DIP flexion
Tip to tip prehension
pad to side prehension (lateral pinch)
203
Pistol grip
Ring and little finger long flexors shorten over > range
Results in loss of tension
If object heavy, it is wider ulnarly
Limits MCP/IP flex while wrist ext stabilize wrist against strong contraction
If a gentle grip is necessary, object may be thinner ulnarly like a wine glass
