bajs Flashcards
(111 cards)
1
Q
What is the main injury mechanism for contusion?
a) Inflammation
b) Rotational acceleration of the head
c) Ruptured bridging veins
d) Compression of the brain tissue
e) Pressure due to swelling of the brain tissue
A
Brain contact with rigid intracranial structures (e?)
2
Q
General injury mechanisms?
A
1.) Concentrated loading/Penetrating injuries
Sharp surfaces, local tissue affected, injuries less sensitive to loading rates
2.) Blunt loading/Non-penetrating Injuries
Forces distributed over larger areas. Distant tissues affected, Injuries more sensitive to loading rates
3
Q
What types of epithelial tissue is there?
A
-Simple squamos, simple cubodial, simple columnar, stratified squamous, stratified cuboidal, stratified columnar
It is important to know these qualities in order to predict injuries in the future
4
Q
When did the 3-point belt become standard in cars?
A
1959 - Standard in front seats Volvo Cars
1967 - Standard in rear seats
5
Q
According to causes of fatality in the US, which are the 4 most common?
According to the same study, which causes the most lost years of productive life?
A
Heart disease, Cancer, Stroke and Accidents(
6
Q
According to US fatality statistics (2012), what types of crashes kill people?
A
Front 75 %
Rear, left, right equally divided over the rest 25 %
7
Q
According to Swedish Medical care data, what road users were injured the most and had the most hospitalized days?
A
Car drivers:
3475 number of hospitalized, 29 300 hosp. days
Bike users:
4912 number of hospitalized, 26 000 hosp. days
8
Q
What can you use road crash test data for?
A
Identify priorities
- Accident scenarios
- Road user groups most affected
- Black spots (locations with most crashes)
Evaluate performance on safety technologies
- Retrospective
- Prospective
9
Q
What levels of crash data are there?
A
Macroscopic level
- statistical data (police)
Intermediate level
- (Insurance)
Microscopic level
- in-depth data (research)
10
Q
Skeletal muscles
A
- Attached to bones (or some facial muscles) to skin
- Single, very long, cylindrical, multinucleate cells with very obvious striations
- Very energy consuming
- Protection and movement
11
Q
Give 5 examples of crash data bases
A
- NASS (US)
- CIREN (US)
- FARS (US)
- STRADA police (SWE)
- STRADA hospital (SWE)
12
Q
The KABCO scale used in the US, what do the characters mean? (Instead of AIS, but AIS is more detailed and reliable description)
A
K = killed A = incapacitating injury B = nonincapacitating injury C = possible injury O = not injured
13
Q
Name 3 different study/research designs
A
- Experimental methods(in-depth knowledge, rare phenomenas)
- Non-experimental or observational studies(
- Case study
14
Q
Explain reliability and validity
A
Reliability:
The degree to which a measure represents the true level of the property being measured (precision)
Validity:
The extent to which a test measures what it claims to measure (accuracy)
15
Q
What layers can the skin be divided into?
A
- Epidermis (epithelium)
* Water proofing
* Barrier to infection
* Outer layer - Dermis
* Connective tissue
* Cushions the body from stress and strain
( - Subcutis (hypodermis))
16
Q
What are ligaments?
A
- Connect bones together
- 6% maximum strain (normally stretched when ex moving or sitting)
17
Q
What are the three types of cartilage?
A
- Hyaline: (few cartilage cells: provide stiff but flexible support, reduces friction) found in nose, ears, trachea, parts of the larynx, and smaller respiratory tubes
- Elastic: (cells close together: provides support, but may return to original shape) found in ear flaps and part of the larynx
- Fibrous cartilage: (least amounts of cells: resist compression, prevent bone to bone contact) found in spine and menisci
18
Q
What is cartilage?
A
The collagen fibers are oriented so that they in combination with the fluid damp compression loads and enables sliding with low friction
- Composed of chondrocytes (=specialized cells) which produce extracellular matrix and is supplied by diffusion
- Does not contain blood
- Grows and repairs more slowly
- Compression or flexion of the cartilage generates the pumping action, which assists the diffusion
19
Q
What are the functions of the skin?
A
- Defense from external factors
- Control water loss
- Insulation
- Temperature regulation
20
Q
What is fat?
A
- Storage of energy
- Causing injuries to fatty tissue –> injury to the cells –> unable to store fat as well –> fat ends up in the blood
- Visceral fat: Surrounds internal organs
- Subcutaneous fat: located beneath the skin
- Bone marrow: yellow bone marrow
21
Q
What are the three types of cartilage?
A
- Hyaline: (few cartilage cells) found in nose, ears, trachea, parts of the larynx, and smaller respiratory tubes
- Elastic: (cells close together) found in ear flaps and part of the larynx
- Fibrous cartilage: (least amount of cells) found in spine and menisci
22
Q
Vertebral disc
A
Annulus = walls of disc
- Annulus gives a high internal pressure which can take up the force (it inhibits radial expansion of the nucleus)
23
Q
Describe the two different types of statistics
A
Descriptive statistics:
- Describes and summarize the collected data in quantitative terms. (Central tendency, variability, Correlation)
Inferential statistics:
- Risk difference, risk ration and Odds ratio(Estimation Statistics, Hypothesis testing)
24
Q
Define Confounding
A
Confusion or mixing of effects that implies that the effect of the exposure is mixed together with the effect of another variable, leading to a bias.
Can be solved with stratification, which means dividing data into different groups and do the testing with instead.
25
What two materials does bone consist of?
- Compact (cortical) bone (usually lines spongy bone)
| - Spongy (cancellous) bone
26
Accurate symptoms following TBI, both Mild and Moderate to severe
Mild:
- Brief period on unconsciousness
- Dizziness
- Headache
- Confusion
- Sensory problems
Moderate to severe:
- Persistent headache
- Nausea
- Spasm
- Dilation of eye pupils
- Slurred speech
- Loss of coordination
27
What is the skeleton good for?
1. Support
2. Protection (ex for the central nervous
3. Movement
4. Mineral Storage
5. Blood cell information
206 bones
If injured, mineral and fat leaks which affects RBC formation
28
What are long bones?
- Longer than wide
- Primarily compact bone, but spongy in the interior
- Ex. humerus, bones in your finger
29
Three facts about the scull bone
- Irregular surface ( in order to keep the brain in place when rotating the head. The drawback is when the head changes rotation in a crash, there will then be a lot of bruises and the uneven surface injuries the brain. Not fine nowadays when high speed injuries)
- Small holes for arteries and veins, and cranial nerves
- Foramen magnum ( Hole in the skull leading to the brain stem, creating problems with heart rate, breathing etc.)
30
Division of the brain and nervous system
Anatomical division: CNS - PNS
Physiological division: Somatic - Autonomous
Nerve fibre direction: afferent(in) - efferent(out) of the brain
Histological: Gray and white matter
31
What are short bones?
- Cube like
- Primarily spongy bone
- Ex. wrist bones
32
What are the functions of the ganglia in the brain stem?
Breathing, heart rate, blood pressure
33
What are irregular bones?
- Everything that does not fit the other classifications (lon, short, and flat bones)
- Complex shape
- Mostly spongy bone
- Ex. vertebrae, pelvis
34
What are muscles good for?
1. Movement
2. Protection
3. Posture
4. Stabilizes
5. Heat
35
How does muscle contraction work?
- Multiple fiber summation: weak signals, meaning smaller motor units are stimulated first
- Frequency summation: control contraction with the frequency of the signal
* Action potentials do not arrive at muscles synchronously, and, during a contraction, some fraction of the fibers in the muscle will be firing at any given time.
36
Different types of muscle contraction
- Motor unit (motor neuron or muscle fibers)
- Twitch (response to single brief stimulus)
- Treppe (Increased contraction in response to multiple stimuli of same strength) (Why you should warm up before exercise)
- Tetanic (ortetanizedstate),incompleteand complete
- Isotonic ‐ Isometric
37
Define the two different groups of TBI and their under groups
1. ) Focal injuries
- Contusions
- Hematomas
2. ) Diffuse injuries
- Concussions
- Diffuse axon injuries
38
TBI: Contusion
Are bruises on the brain. Common at inferior surfaces of frontal and temporal lobes. That is due to the very thin bone at temporal lobe
Mechanism: Brain contact with ridge intracranial structures
39
TBI: Hematoma
Blod forms a hematoma that compresses the brain tissue
Bridging veins:
- Subdural hematoma
- Rotation injury
Meningal atrery:
- Epidural and extradural hematoma
- Fractures
40
Which muscle injuries may occur?
- Lacerations: due to tear
- Perforation: result of a penetration
- Rupture: break or burst
- Contusion/bruising: injury in which the skin is not broken
41
What are the functions of the joints?
- Articulation of the rigid bodies
| - Connect elements of the skeleton
42
Subarachnoid hematoma
Bleeding into the cerebrospinal fluid of the subarachnoid space. Artery raptures.
Permanent brain damage from ischemia or from the presence of hematoma.
Mechanism: Rotational acceleration in conjunction with aneurysm.
43
What are fibrous joints?
- Sutures (bone only)
- Syndesmoses (sheet of ligament)
- Gomphoses (teeth)
44
Symptoms of hematoma?
Immediately to several weeks after a blow to your head
- "Worst heacache of their lives"
- Vomiting
- Slurred speech
- Pupils are unequal size
As more and more blood flows into the narrow space between the brain and skull
- Unconsciousness
- Lethargy
45
Concussion
(Hjärnskakning)
Most common in traffic injuries and among children.
Can get retro- or anterograde amnesia and the duration of the amnesia correlates with the severity of the concussion.
Can also get Post concussion syndrome, which can include memory loss, dizziness, and depression.
Mechanism: Rotational or linear acceleration of the head
46
Diffuse Axon Injury (DAI)
Lesions in the white matter (corpus callosum, peduncles and thalamus). Axons are torn at the site of stretch.
There is an unconscious and vegetative state. These are very severe symptoms, 90 % never regain consciousness again.
Mechanisms: Shearing forces due to rotational acceleration. Stretching axons that traverse junctions between areas of different density.
47
AIS, what is it and what does it stand for
Abbreviated Injury Scale score for the brain.
48
What are the properties of the human tissue?
- Individual spread (ex. mechanical properties due to age, gender, hormones, etc)
- Composite structure
- Complex material models (Nonlinearity, Viscoelasticity, Anisotropy)
49
What is the human made of?
- Collagen and elastin (ligaments, tendons, bones, etc)
- Actin, myosin (muscles)
- Blood, water, CSF (Fluids)
- Minerals (Hydroxyapatit)
50
What are the mechanical properties of bone?
- Anisotropic
- Inhomogeneous
- Nonlinear
- Viscoelastic
- Self repair
- Change properties due to loading (Wolf's law)
51
What is so special about TBI injuries? (Two factors)
- Even a moderate bump can cause damage to the brain
| - Damage to limbs may often be repaired while brain damage many times causes permanent harm
52
What is trabecular bone?
- Cancellous bone
- Porous bone
It can adapt, ex. joint surface in the knee
53
What are mechanical properties of compact bone?
Orthotropic: different material properties or strength in different orthogonal directions
54
What is the structural composition of the soft tissues?
- Cells (fibroblasts)
- Water
- Collagen
- Elastin
- Ground substance
55
What is elastin?
The most “linearly” elastic biosolid known, at least up to 60% strain.
Does not want to absorb energy --> very, very warm
56
What is ground substance?
- Hydrophilic gel
- Composition varies with the tissue
- Mucopolysaccharides (sockerlösning) and tissue fluid
- Mobility of water in ground substance --> viscoelastic material properties
- Low Young's modulus but high Poissons Ratio
57
What is the viscoelastic response due to the properties of the ground substance?
- Fluid flow during loading
- Shear forces between the matrix and fibers during fiber straightening
- Rate dependent strength, stiffness and energy absorption
58
How are the ligaments and tendons between 0-20 years?
Strength increase due to increased number of cross‐links within and between collagen fibers
59
How does the ligaments and tendons change when you are 20+ years?
Strength decreases due to aging
60
What are the characteristics of the skin?
- Nonlinear
- Viscoelastic
- Anisotropic (orthotropic)
- Fiber orientation according to " Langer lines" (Young's modulus is 4 times higher parallell to the Langer's lines compared to perpendicular to Langer's lines
61
What are the characteristics with the intervertebral disc?
- 10 times stiffer in compression than torsion, shear or flexion
- The almost incompressible properties of the NP result in tensile loading of the collagen fibers when the disc is compressed
- Rate dependent properties
- Viscoelasticity (fluid flow)
62
What are the injury control strategies?
- Accident conditions
- Crashworthiness (change how the car deforms?)
- Occupant motion (How do you move inside the car?)
- Impact contact (How can you absorb the energy?)
63
Give example of 5 long term symptoms of TBI
Trouble remembering, concentrating, making decisions and controlling impulses.
Suffer from serious motor, emotions and sensory impairments
64
Mention facts about the scalp:
5-7 mm thick and consists of:
- Skin
- Connective tissue ( thin layer of fat and fibrous tissue)
- Muscles
- Aponeurosis - thick layer of dense fibrous tissue
- Loose areolar connective tissue (provides separation between the three layers and pericranium)
- Pericranium (periosteum of cranial bones)
65
What is crash worthiness?
- Absorbe energy and distribute over time
- Keeping occupant intact
- Assessed by retrospectively analyzing injury risk, or analyzing patterns, dummies, HBM, etc
Optimal crash worthiness: entire front of the car should deform so that the acceleration is as low as possible (for all vehicles)
- Adjust to different velocities by having an adaptable front (softer in low velocities and harder in high velocities)
66
Name three viscoelastic phenomena in the human body
- Creep
- Relaxation
- Hysterisis
67
Main principle for restraining a car occupant
The “stiffness” of the restraint must not exceed that of the occupant’s body region it restrains during a collision
68
What is the advantage with Falx cerebri?
It supports some loading so the brain won't move as much relative to the brain.
69
What are the injury reduction strategies?
- Exposure control (ex. stay at home so you don't encounter traffic)
- Crash prevention (active safety)
- Behavior changes (Don't text, sleep, etc.)
- Post injury management (send injured person to local hospital to stop bleedings, etc. then send to trauma or other way around)
- Injury control
70
What are accident conditions?
- Speed
- Energy transfer
- Direction and location of the principle force on the vehicle/body (rollover, multiple collisions, trees, etc.)
71
What is crash worthiness?
- Absorbe energy and distribute over time
- Keeping occupant intact
- Assessed by retrospectively analyzing injury risk, or analyzing patterns, dummies, HBM, etc
Optimal crash worthiness: entire front of the car should deform so that the acceleration is as low as possible (for all vehicles)
- Adjust to different velocities by having an adaptable front (softer in low velocities and harder in high velocities)
72
What is occupant motion?
- Affects what type of structures you hit in the car (ex. 3-point belt)
- 4-point belt: less rotation, more pressure on the sternum, more broken ribs
* Rotation absorbed energy better
* Belts needs to be softer and pay out more in order to be safer
- Airbags controls the neck injury risk
- Improved belt interaction with new shoulder on test dummy
73
Why do we need Injury Risk Functions?
- Very important to consider statistics when you write your paper
- You load something, then you see what risk there is for injury ( ≈ probability ). Need to specify which AIS a certain risk function is for.
- Need to relate input load measurements to failure risk
- Instead of doing calculations and model, you can skip directly to impactor testing and measure.
74
What types of data censoring are there?
- Right or left censoring (above/below a certain value but not by how much, very common)
- Interval censoring
- Exact data
75
What are the three principle injury mechanisms that usually can be distinguished in thorax injuries?
- Elastic
- Viscous
- Inertial
76
What is a pretensioner?
It removes the slack of the belt which reduces the maximum chest acceleration
77
How do you choose a method to construct injury risk functions?
- Prior knowledge
- "Commonly used" functions
- "Efficient functions"
- Information Criteria
- ROC curves
78
How could you prevent lower limb injuries?
- Inflate a structure underneath the carpet which is made of metal to ensure good timing and absorb energy.
79
What is dual injury mechanism?
Something might break in several different ways (it is quite rare). Need to make sure you are testing what you really want to test.
80
What are the functions of the Cerebrospinal Fluid?
- Protection (cushion to the head)
- Buoyance (reduce net weight of the brain and pressure at the base of the brain)
- Excretion of waste products
- Endocrine medium for the brain (transport of hormones)
81
Which are the meaning of the head, from outside to inside (6 st)
```
Dura mater (subdural space)
Arachnoidea mater (subarachnoidal space, CFS)
Pia mater
Cerebral cortex (Gyri and sulci)
White matter
Basal ganglia
```
82
Valt fractures?
Google it
83
Are there any differences between the four types of vulnerable road users, time of day, rural/urban, etc.?
- Cyclists impact further up relative the vehicle and account for a larger amount of permanently injured
- Mopeds and cyclists often hit the side of the car or are hit from behind by a car and have a higher speed than pedestrians
- Pedestrians: Common with knee injury since that's where the car hits.
84
How do you raise interest of the car industry reducing vulnerable road user accidents?
EuroNCAP could integrate a test where pedestrian score is included in the total score of the car
85
What does a vulnerable road user car looks like?
- Low placed engine
- Reduced aggressiveness of vehicle fronts (ex. double deformable front of the car with flat structure so you don't overbend the knee)
- Reduced height of bumper (for children)
- A-pillar airbag
86
What are the commonly used Injury Risk Functions?
- Mertz/Weber: widely used in the 1980's but not anymore
- Certainty Method: not used anymore
- Logistic Regression: Drawback is that it doesn't regard to data censoring. But you can input as many variables as you want (easiest)
- Consistent Threshold Estimate (CTE): Good but non-parametric, i.e. makes no assumption on how the final curve looks like. Not used today.
- Survival Analysis: Similar to CTE but not used today (best)
- Normal CDF: Don't consider the uninjured people at all. People still use it, but not a good idea to discard data
87
Why are seniors in majority in fatal crashes?
Seniors are fragile = easy to break
| Seniors are frail = when injured more likely to die
88
What is logistic regression?
- Not necessarily monotonously increasing
- Fits logistic function to data
- No reflection of data censoring
89
What is survival analysis?
- Nonparametric and parametric (easy)
- Data censoring is reflected
- Goes through 0/0 (in a plot) and increasing with load
- Commonly used
90
What is a vulnerable road user?
Unshielded
- Pedestrians (very absent minded)
- Cyclists
- Mopeds
- Motorcycles
Elderly and children
91
How big is the vulnerable road user issue?
- 50 million injured in traffic world wide each year
| - China and India has a lot of issues since there are about 75% pedestrians
92
What are the most common and most severe injuries in vulnerable road users?
- Most common to injure lower extremities and head
- Young are very exposed but more minor injuries while elderly have more serious injuries.
- AIS4 for lower extremities is amputation above the knee. AIS2 is ruptured ACL (främre korsband)
- AIS4 for head is coma for 6 hours or more
93
What are human kinematics in accidents with cars?
There are 4 different phases of pedestrian injury:
- Primary impact: impact with car
- Flight phase: you move upwards and forwards (when in the air)
- Secondary impact: Hitting the ground again 10 meters away
- Sliding phase: sliding on the ground after impact. Can cause a lot of injuries as well
94
What is the influence of human, size, age, gender, etc with vulnerable road users?
?
95
What are the typical scenarios for side impacts?
- All injuries --> single young drivers
| - Fatalities --> senior occupant with neighbor
96
What is the purpose of the use of biological models?
- Kinematics: model evaluation and injury prevention
- Injury: understanding governing mechanism and injury risk curve construction
- For understanding: to introduce restraints, injury diagnosis, and injury treatment and medication
97
What are the advantages and disadvantages with volunteer testing?
+ Proper soft tissue response
+ Detailed kinematics from high speed cameras
+ May measure muscle response (surface or percutaneous EMG)
- No spread of data (common to have male students or military)
- Hard to relax properly, compromising the results of the impact (muscles tense)
- Are not allowed to injure volunteers (no injury data)
- Awareness of impact
98
What are the advantages and disadvantages with PMHS testing?
+ Testing to failure
+ Test isolated body segments (ex. arm, head, leg)
+ Detailed material data
+ Local and "global" kinematics
- Limited number (typically elderly, short, bad fitness)
- Soft tissue conditions varies
- Can't measure pain, hard to find soft tissue damage
99
Epidural and extraural hematoma
Artery raptures between dura and skull. The risk of dying from epidural hematoma is substantial.
Mechanism most temporal bone fracture from falls and violence, not rotational!
```
Epidural = Artery bleeding in the dura
Extradural = Artery bleeding between the dura and brain
```
100
Subdural hematoma
Veins raptured between dura and arachnoid.
There are 3 types: Acute, sub-acute and Chronic
Mechanism:
- Lateration from penetrating objects and bone fragments.
- Large contusions
- Tearing of bridging veins due to rotational movements.
- Age related due to shrinking of the brain.
101
Where do the ribs usually crack?
Where the cartilage turns into bone
102
What are important characteristics for human like surrogates?
- Easy yo handle (practical in the lab)
- As deformable as a human, but able to do repeatable tests
- Predict injury risks, they do not break as a human, meaning we need load cells and head rotational, etc. Compare data to risk curve
- Anthropometry (shape, size, and mass distribution)
- Bio-fidelity (human-like stiffness of surface and joints)
- Repeatability (exactly the same response every time)
- Reproducibility (two dummy individuals should give the same response)
- Sensitivity (inputs affecting injury risk, ex. variation)
- Instrumentation (measure output signals known to indicate injury risk)
- Durability (can withstand serious crash loadings without damage)
103
Where do the ribs usually crack?
Where the cartilage turns into bone
104
Intracerebral hematoma
Blood in the white matter of the brain (Much like stroke, but we don't really know why) combined with white matter shear injuries.
Blood irritates the brain tissue causing swelling or hematoma
Mechanism: Laceration, sheering(?)
105
AIS, what is it and what does it stand for
Abbreviated Injury Scale score for the brain.
106
THOR dummy is supposed to replace .... in .... collision tests
HYBRID III
| frontal
107
Which restraint systems protects the pedestrian?
- Geometry
- Stiffness
- Poop up hoods and airbags
108
Which restrain systems protects the occupant in a frontal collision?
- Airbag
- Deformable structures
- Belt system
109
Explain rotational trauma of the brain.
The folding in the bran creates a lot of problems because they will move relative to each other.
- Rotational trauma: right and left hemisphere moves opposite since they are two units. Causes blackout injuries to the connections between the hemispheres.
110
What are the functions of epithelial tissue?
1. Protection
2. Absorption
3. Filtration
4. Secretion
5. Transcellular transport
6. Excretion
7. Sensory reception
111
Which are the 5 parts of the spine?
- Cervical 7 units
- Thoracic 12 units
- Lumbar 5 units
- Sacrum (5 units)
- Coccyx (4 units)
