1
Q
Equipment in a forensic lab
A
- tables and benches
- sink with hot and cold water
- fume hood
- measuring equipment
- drying racks
- reference casts
2
Q
What size of table?
A
2x1 meters -> length of a skeleton
3
Q
What measuring equipment is used?
A
calibers and osteometric boards
4
Q
Methodological and safety issues in the lab
A
- Security: maintain chain of custody (restricted access, alarms, log ppl coming in and out, keep all remains separate.
- Separation of evidence units: keep skeletons separate (only have one out at a time!)
- work environment: fume hood for chemicals, stay up to date on vaccines, clean everything carefully (1% bleach solution), wear protective clothing
5
Q
Preparation of remains (steps)
A
- examination for soft tissue trauma
- bulk soft tissue removal
- disarticulation
- residual soft tissue removal
- stabilizing remains
6
Q
examination for soft tissue trauma
A
look for trauma to flesh
7
Q
Bulk soft tissue removal
A
Fully clean off the soft tissue, using a scalpel and tissue scissors
-> remove muscles of torso, then limbs
-> cut tendons and peel away
8
Q
Alternative method for bulk tissue removal
A
Dermestid beetle larvae
- takes 2-3 weeks for the beetles to eat the flesh
- smells, have to take care of the beetles
- keep some beetles afterwards for sampling
9
Q
Disarticulation
A
- separate joints and their articulated bones (skull from spine, arms from torso, pelvis from spine, legs from pelvis)
- after those major removals separate the elbow and leg joint
10
Q
Residual soft tissue removal
A
- soak bones in water to soften tissue, then simmer them in water and detergent for a couple of days
- degrease with benzol afterward, which takes a couple of days
- finally, bleach with hydrogen peroxide/potassium hydroxide for about a day
11
Q
Alternative way of residual soft tissue removal
A
An antiformalin solution, which has stronger chemicals. It takes less time but can cause the bones to disintegrate
12
Q
Stabilizing remains
A
- preserve bones in Alvar or PVA (coating)
- not used anymore because it alters the composition of bones
13
Q
Reconstruction
A
- use a reversible adhesive, just in case you make a mistake
- don’t add stand-ins for bones!
14
Q
Sorting Commingled remains
A
Commingled remains: bones of many individuals mixed up
- determine MNI
- group bones by type, categorize them
- determine the number of people based on the number of bones
15
Q
Reassembly
A
- lay bones out in anatomical position and double check for:
duplication, consistency in size, if joints fit together (joint surface concurrence
16
Q
Inventory
A
cross check with the field inventory, and mark all bones with a case number
17
Q
Visual skeletal inventory & numerical inventory
A
Visual: pre-existing skeleton drawing (one for adults, adolescents, and children) where you color in the bones that are present
Numerical: mark fragments, number of fragments, and lefts and rights. Mark % of bone present and % of skeleton present, along with how well the the exterior is preserved.
18
Q
What is sex?
A
biological sex -> male or female, along with categories for indeterminable and possibles
19
Q
Sexual dimorphism
A
differences in size and shape between the two biological sexes
20
Q
What is the accuracy in determining sex for the following portions of the skeleton?
1. Whole skeleton
2. Just pelvis
3. Just skull
4. Just long bones
A
- 90-100%
- 90-95%
- 80-90%
- 80%
21
Q
What’s the difference between a male and female pelvis?
A
Male: large and robust
Female: small and gracile
22
Q
What’s the difference between a male and female ilium?
A
Male: high and vertical
Female: low and flat
23
Q
What’s the difference between a male and female subpubic angle?
A
Male: v-shaped
Female: U-shaped
24
Q
What’s the difference between a male and female pubic shape?
A
Male: narrow and rectangular
Female: broad and square
25
What's the difference between a male and female pelvic inlet?
Male: heart-shaped
Female: circular/elliptical
26
What's the difference between a male and female obturator foramen?
Male: large and ovoid
Female: small and triangular
27
What's the difference between a male and female greater sciatic notch?
Male: narrow
Female: wide
28
What's the difference between a male and female prearicular sulcus?
Male: rare
Female: well-developed
29
What's the difference between a male and female sacrum?
Male: sacrum protrudes, and is long and narrow
Female: sacrum is tucked away, and is short and broad
30
What are the phenice traits?
These are the golden traits for estimating sex, with an accuracy of 95%. They include:
1. Ventral Arc
2. Subpubic concavity
3. ischiopubic ramus ridge
31
What's the difference between a male and female ventral arc?
Male: slight/absent
Female: strong
32
What's the difference between a male and female subpubic concavity?
Male: convex
Female: concave
33
What's the difference between a male and female ischiopubic ramus ridge?
Male: broad and flat
Female: narrow, crest-like
34
Washburn's ischium-pubic index
(pubic length/ischium length) x 100
<84 = male, 94+ = female
68% accuracy for unknown ancestry, 83-91% if ancestry is known
35
What's the difference between a male and female skull?
Male: large and rugged
Female: small and smooth
36
What's the difference between a male and female chin?
Male: broad
Female: pointed
37
What's the difference between a male and female mastoid process?
Male: large, projecting
Female: small, non-projecting
38
What's the difference between a male and female brow ridge?
Male: large
Female: small to none
39
What's the difference between a male and female frontal?
Male: slanted
Female: high, rounded
40
What's the difference between a male and female suborpital margin?
Male: rounded
Female: sharp
41
What's the difference between a male and female nuchal area?
Male: rugged, hooked
Female: smooth, hookless
42
How would you determine sex based on the traits from the skull?
- score the traits 1-5, female - male
- put into corresponding discriminant function
y > 0 = female
y < 0 = male
43
What is age?
1. chronological age: measured from when you're born
2. biological age: developmental landmarks, such as puberty
3. socio-cultural age: when you're socially an adult (18), or other social markers such as quinceaneras, bar mitzvahs, and sweet sixteens
44
True or false: a lunar month is four weeks
true
45
Life stages of juveniles
1. Prenatal
2. Infancy
3. Childhood
4. Adolescence
46
Prenatal
begins with conception, and ends at birth
Embryo: first 8 weeks
Fetus: Ninth week to birth
47
Infancy
when a baby is nursing (cultural)
Infant: birth to one year
Perinate: around the time of birth
Neonate: first four weeks after birth
48
Childhood
from weaning to puberty
Early childhood: 1 to 4 years
Late childhood: 5 to 9 years
49
Adolescence
from puberty to the end of growth
Early adolescent: 10 to 14 years
Late adolescent: 15 to 17 years
50
how to do fetal aging with long bones
- take measurement (cm) and put in the regression equation
- correlate answer with lunar months
51
how to do aging with ossification centers
different epiphyses fuse throughout different periods of life
52
How to do aging with teeth
development of crowns, roots, adult teeth growing underneath
53
Skeletal Collections
Terry Collection
Hamman Todd Collection
Raymond Dart Collection
54
British System of Aging:
Young Adult: 18-25
Young Middle Adult: 26-35
Old Middle Adult: 35-45 years
Old Adult: 46+
55
Epiphyseal Fusion
some bones are still in the process of fusing well into adulthood (clavicle, sternum, os coxa, scarum)
56
Suchey-Brooks Method
Uses the face of the pubic symphysis, which goes through 6 different phases
1. covered in ridges and furrows
2. ridges and furrows get obliterated/filled in
3. bone is built up around joint margins
4. a continuous rim of bone is formed
5. rim breaks down
6. symphyseal surface becomes porous and pitted
57
Sternal Rib Ends
58
Skull?
59
What is stature?
Measured Stature: measurement of height
Forensic Stature: reconstruction of height based on proxies (bones)
Cadaver stature: measurement of a cadaver
60
Methodological Problems of Living Stature
- way and means of measurement, along with the position of the individual being measured
- reported stature (ppl estimating their own height for licenses)
- secular changes in height over time
61
Fully Method
Most accurate method for estimating stature. It involves measurements of the cranial height, vertebral column length, leg length, and foot height. However, needing all these bones can make this method very inaccessible.
62
Vertebral Method + who made it
TIbbets
involves the measurement of the body of vertebrae (NOT the neural arches)
discriminant functions are divided by sex
63
Long Bone Length Method - Trotter
utilizes the measurements of long bones
discriminant functions divided by race + sex
64
Metatarsals and Metacarpals - Meadows, Byers
it's in the name
discriminant functions divided by race + sex
65
Fragmentary Long Bones - Steele
discriminant functions used to recreate the length of the long bone, then are plugged into long bone length methods to determine stature
66
Correction Factors: age
decrease statures after age - this is subtracted after doing all calculations
67
Correction Factors: bone shrinkage
Bones that are dry and have been sitting out for a while are subject to shrinkage, by about 1.5%
add this number to the length of the bone before calculating
68
Ancestry
69
What does the Egyptian's depiction of various races show us?
even in small geographical locations, phenotypes can vary a lot
70
Cardus Cinnaeus (1707-1778)
first to use binomal nomenclature with scientific names
wanted to create a classification system for humans, defined four groups
- H. sapiens Europeus albescens: European "whites“
- H. sapiens Africanus negreus: African "black” people
- H. sapiens Asiaticus fucus: Asian "dark“ people
- H. sapiens Americanus rubescens - "red“ people
from the Americas
71
Johann Friedrich Blumebach (1752 - 1840)
studied differences in ancestry based on the skull, created five groups
- Mongolian (yellow)
- American (red)
- Caucasian (white)
- Malayan (brown)
- Negroid (black)
these conclusions are based on extremes, and the categories are arbitrary
72
World History Encyclopedia - 1907
- included much more categories, largely based on ethnicity
- added a ranking
73
Biological Determinism
the idea that our traits determine our abilities
74
Eugenics
the idea that you can get rid of the "less desirable" traits that are heritable in the population (think Nazis!)
75
Typological Model
a regular reoccurrence of selected skeletal traits
- can really only be used when there's no gene flow between population
- is ethnocentric and focuses on cultural, not biological groups
76
Population Model
populations that would regularly breed
- groups of people bounded by things like nationality or geography (ex. canadians)
77
Clinal Model
genetically inherited traits that change gradually in frequency from one geographic area to another
- caused due to the flow and movement of people
- groups that have the traits you're looking at are called "clines"
- involves discrete (this or that) traits such as blood type
78
phenotypic traits
what you see
79
genotypic traits
what's in your genes, inherited
80
polymorphic/polygenic traits
complex traits with no boundaries, such as eye color
81
Adaptive Significance of Human Variation
results of adaptations to environmental conditions
-> short term adaptations (like being able to tan)
-> long term adaptations (like height)
82
3 main ancestral groups
Asian, Black, White
- Native Americans are grouped with Asian
83
Differences between ancestry for the nose root distance?
white: wide
asian: narrow
black: narrow
84
Differences between ancestry for the nose root position?
white: higher
asian: lower
black: lower
85
Differences between ancestry for the nose spine?
white: pronounced
asian: small
black: absent
86
Differences between ancestry for the nose root width?
white: narrow
asian: intermediate
black: wide
87
Differences between ancestry for the shape of nasal aperture?
white: isosceles triangle
asian: in between
black: equilateral triangle
88
Differences between ancestry for the nose ridge/sill?
white: distinct
asian: in between
black: indistinct + guttering
89
Differences between ancestry for the face profile?
white: more vertical
asian: intermediate
black: more projection
90
Differences between ancestry for facial width?
white: narrow
black: narrow
asian: wide
91
Differences between ancestry for the orbit shape?
white: angular
black: rectangular
asian: circular
92
Differences between ancestry for the lower eye border?
asian: projecting
white: vertical
black: vertical
93
Differences between ancestry for the brow ridges and muscle markings?
white: pronounced
black: less pronounced
asian: less pronounced
94
Differences between ancestry for the sutures?
white: straight/linear
black: straight/linear
asian: complex/wavy
95
post-bregmatic depression...
mainly found in black individuals, or skulls which have been modified
96
what ancestry has the most dental crowding?
white
97
Differences between ancestry for the dental arch?
white: parabolic
asian: rounded
black: u-shaped
98
incisor shape
white and black: underside is flat, spatulate
Asian: shovel shaped, indentations
99
Differences between ancestry for the chin?
white: pointed
asian: rounded
black: blunt
100
Which ancestry has a more vertical ramus?
Asian
101
Differences between ancestry for the femur shaft?
white: curvature
asian: curvature
black: vertical
102
Differences between ancestry for the femur head?
when laid flat on table:
asian: vertical, femoral torsion
black: more slanted, horizontal
white: intermediate
103
What are some metric methods for determining ancestry?
Indexes:
maxillofrontal
zygoorbital
alpha
platymeric index (femur)
104
What do you need in order to use the discriminant functions?
all of the measurements!
105
What did Giles and Elliot do?
created discriminant functions to determine sex for diff ancestries, 90%+ accuracy
ARCL 228
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