Midterm 1 Flashcards
1
Q
MSD
A
Musculoskeletal Disorder
2
Q
WMSD
A
Work related Musculoskeletal Disorder
3
Q
UEMSD
A
Upper Extremity Musculoskeletal Disorder
4
Q
CTD
A
Cumulative Trauma Disorder
5
Q
Two ways visible disease changes?
A
1) How much disease there is
Changes in population body weight, major shifts in working conditions
2) Awareness of disease
Able to see more clinical disease when people are able to know and identify it - i.e. carpel tunnel syndrome
6
Q
Tissue Types for UEDs
A
Tendon Muscle Nerve Vascular Bursal Bone & Cartilage Ligament Fascia
7
Q
Approximate cost of compensated shoulder injuries in Canada?
A
$60,000 direct cost + $60,000 indirect cost / injury
$1,170,000 Total
8
Q
Function of tendon
A
transmit force from a muscle to a bone (only linearly, not transverse)
9
Q
Tendon Disorders
A
Excessive / Incorrect Loading
Results inflammation and then deformation & tears
10
Q
Function of muscle
A
Actuators of the lever system of the skeleton:
- initiate/maintain motion/force transmission
- joint stabilization
11
Q
Muscle Disorders
A
external forces on passive tissues
straining sarcomeres with eccentric contractions
12
Q
Function of nerves
A
send signals throughout the body
13
Q
Nerve Disorders
A
Entrapment from muscle, bone, tendon, ligament
14
Q
Function of vasculature
A
Material highway to/from cells for normal function
15
Q
Vasculature Disorders
A
Ischemia through occlusion / constriction / obstruction
16
Q
Function of Bursa
A
sac-like body cavity to reduce stress in a joint
17
Q
Bursa Disorders
A
Friction and trauma
18
Q
Function of Bone
A
Form - structure & protection
Function - muscle attachment to allow motion
Factories - production of material
19
Q
Function of Cartilage
A
Force, support, shock absorption
20
Q
Bone and Cartilage Disorders
A
Inflammation and degeneration
21
Q
Stability and Mobility of the Shoulder
A
Most mobile
Most instable
22
Q
Stability and Mobility of Sternoclavicular Joint
A
SC joint has good stability - provided by costoclavicular ligament
Very limited ROM
23
Q
Degrees of Freedom for SC Joint
A
1 - Elevation / Depression (30-35)
2 - Anterior / Posterior (35)
3 - Long Axis (40-45)
24
Q
Kinematic Redundancy
A
able to get to distal segment through multiple proximal segments
i.e. shoulder girdle to hand
25
Degrees of Freedom for Scapulothoracic Gliding Plane
1 + 2 - Translational
3 - Tipping
4 - Rotation
5 - Protraction / Retraction
26
GH Joint Movements
Abduction - 150
Flexion - 180
External/Internal Rotation - 90
27
GH Stability Contributors
```
Muscle Action
Ligaments
Joint Suction
Adhesion
Bony Constraints
```
28
Functions of Shoulder Muscles
Position glenoid for maximum mobility
Articulate the upper arm
Ensure GH stability
provide humeral and whole arm stiffness
29
Bipedalism
Upper extremity functional differentation
| Allows for tool use
30
Bone Structure of Chimpanzee compared to Human
More superior clavicle = more superior glenoid
| Clavicle orients scapula posteriorly - deals with gravity forces better when quadriped
31
What are the benefits to a suprolateral glenoid?
| What are the benefits to a lateral glenoid?
```
Superolateral = better at moving arms overhead, and body weight transferring (quadripedalism, swinging)
Lateral = better at bringing arms together to allow for intricate tool use in field of vision
```
32
What are the benefits to a suprolateral glenoid?
| What are the benefits to a lateral glenoid?
```
Superolateral = better at moving arms overhead, and body weight transferring (quadripedalism, swinging)
Lateral = better at bringing arms together to allow for intricate tool use in field of vision
```
33
Differences in hand and forearm musculature in Humans compared to Chimpanzees
short fascicle length = decreased shortening velocity = decreased force = increased precision
physiological cross-sectional area decreased = lower force capabilities
smaller motor unit size = precision control
34
Differences in distal radial surface morphology?
Chimpanzees have a distal project which locks wrist in place to be able to transmit force while walking quadripedally, decrease wrist extension ability compared to humans
35
Hand differences between chimpanzees and humans?
Longer grasping fingers in chimps = gross grip and weight support
Long thumb length in humans = precision grip and tool usage
36
What are upper extremity advantages humans have?
Fine motor control = material manipulation and tool use
| Long range, high speed throwing = distance protection
37
Prevalence of Proximal Humerus Fractures
Low risk
Increases with age
Women at an increased risk - osteoporosis
38
Mechanisms of Humerus Fractures
FOOSH
| Trauma
39
Classification types of Humerus Fractures
Kocher - based on location of break (greater tuberosity, lesser tuberosity, head, shaft)
Neer - based on number of fragments (2 part vs. 3 part vs. 4 part and classes based on what area fractured)
AO - based on vasculature supply (absence, partial isolation and complete de-vascularization)
40
Clinical Features of Proximal Humerus Fractures
```
Pain
Swelling
Tenderness
Crepitis
Ecchymosis
```
41
Diagnosis of Proximal Humerus Fractures
X-Ray - 3 views
42
Treatment of Proximal Humerus Fractures
```
Initial immobilization - cast
Closed reduction
Skeletal Traction
ORIF
Internal prosthesis (complete joint replacement)
```
43
Complications of Humeral Fractures
```
Vascular injury
Brachial Plexus injury
Frozen shoulder
avascular necrosis
nonunion
malunion
```
44
Prevalence of Scapula Fractures
Very rare
Hard to get to, very well protected by muscle + able to compensate for force by moving in 5 planes of motion
Typically at body or glenoid neck
45
Mechanisms of Scapular Fractures
Lots of force required
46
How does damage to glenoid occur with scapula fractures?
Glenoid rim = combination of compression and shear force
| Glenoid fossa = lots of compression only
47
Clinical Features of Scapular Fractures
Pain
Local tenderness
Swelling
Crepitus
48
Diagnosis of Scapula Fracture
X-ray
49
Classification of Scapula Fractures
Fractures at glenoid neck categorized by location
Type 1 = minimal displacement (more popular)
Type 2 = displacement
50
Treatment of Scapula Fractures
Typically conservatively when nondisplaced
51
Scapula Fractures and Double Displacement of the SSSC
Superior Shoulder Suspensory Complex makes a ring at the GH joint
Major instability of the shoulder occurs when ring becomes broken and incomplete
52
Prevalence of Clavicle Fractures
Frequent fracture and shoulder injury
53
Mechanisms of Clavicle Fractures
Direct and indirect force
FOOSH - main cause
Buckling of clavicle - forces applied at shoulder towards sternum
Stress Fractures
54
Clinical Features of Clavicle Fractures
```
Skin tenting
Drooping shoulder
Pain
Ecchymosis
Angled head to reduce trapezius pull
Fully supported arm weight
```
55
Diagnosis of Clavicle Fractures
X-ray
56
Classification of Clavicle Fractures
Group 1 = break at S bend (most common)
Further broken down to (A=transverse, B=Wedge, C=comminuted)
Group 2 = break at AC joint side
Further broken down to (Type 1 = intact AC, Type 2 = torn AC)
Group 3 = Break at SC joint side
57
Treatment of Clavicle Fractures
Sling support
ORIF
OREF
Typically conservative
58
Complications of Clavicle Fractures
Nonunion
Malunion
Neuro-vascular Sequelae
Post-traumatic arthritis
59
Humeral Head Differences
Humans have lower torsion = increased internal/external rotation = increased angular displacement = increased throwing velocity
60
Clavicle Differences
Chimps = thicker clavicle = increased force absorption = better at weight bearing
61
Scapula Differences
Chimps = superiolateral glenoid = increased arm flexion / decreased arm extension = better overhead reaching
Superiolateral glenoid = pec major pulls medially + inferiorly = overhead reaching
humans = lateral glenoid = pec major horizontally adduction
62
Supraspinatus Differences
Chimps = bigger = better at weight bearing through U.E.
63
Forearms Differences
Primates able to supinate = tool use overall
| Humans = less curves + lighter = less force required to move = increased precision movements
64
Elbow Differences
```
Humans = increased moment arm with flexed elbow
Chimps = increased moment arm with extended elbow
Chimps = deeper trochlear notch = increased stability with extended arm / decreased ROM of arm
```
65
Laxity vs Instability
```
Laxity = asymptomatic, passive translation in joint
Instability = pathological, pain/discomfort/excessive translation
```
66
Laws of GH Stability
1 - Dislocations will not occur if the Net Humeral Joint Reaction Force (NHJRF) is directed within the effective glenoid arc
2 - Humeral head will remain centred in the glenoid fossa if the glenoid and humeral joint surfaces are congruent and NHJRF is directed within the effective glenoid arc
67
Net Humeral Joint Reaction Force (NHJRF)
Combination of:
| Active Muscle Contraction + Passive Muscle Stretch + Inertial Forces + Gravitational Forces + External Forces
68
Effective Glenoid Arc
Arc of the glenoid available to support the head of the humerus in a given direction
69
Components of GH Stability
```
Statically: Articular Version
Articular Conformity
Labrum
Intra-Articular Pressure
Ligaments
Adhesion
Suction Cup
Dynamically: Active Muscle Contraction & Proprioception
```
70
Articular Version
Orientation of glenoid
- 30 degrees frontal plane
- 3 degree upward rotation = small shelf for removing gravity force
71
Articular Conformity
radii differences between humeral head and glenoid articular surface
72
Labrum
Increases surface area = provides concavity compression
| concavity compression = compression of labrum creates a deeper fossa for increased stability
73
Intra-articular Pressure
limits translation + controls rotation
vital stability while inactive
medium pressure is desired
74
Ligaments and Shoulder Stability
mostly passive - increasing ROM
keep joint in position
active during extreme postures - deviations from scapular plane and elevation
