Studied by 5 people
forensic taphonomy
modifications made to the bone that are essentially natural
effects of animal scavenging
scattering/disarticulation of remains
pull limbs apart at torso, gnaw an epiphyses
break bones in particular pattern by trampling or chewing
more than 80% of skeleton recovered = less than 6 months since dead
less than 20% of skeleton recovered = more than 6 months since death
rodents create parallel lines on bones
carnivore activity on bones
Chewing on bone
puncturing
pits (compressed cortical bone)
scoring (parallel lines)
furrows (sharp, deeper)
excessive activity leaving V-shaped marks
sequence of carnivore dismemberment
soft tissue of head and neck
ventral thorax opened, contents of chest eaten, followed by sternum/rib ends
upper limbs
lower limbs
thorax removed, ribs broken
long bones separated from each other
all bones disarticulated, scattered, chewed
weathering
water hydrates bone, sun dries it out
burial damage
bone takes on qualities of burial environment
soil colour permeates bone
root etching
erosion of cortical bone
damage during recovery
water transport phases
body sinks, travels away from initial point of insertion
damage from body scraping, erosion of tissue
damage from currents
body bloats, rises to surface
body parts begin to separate
independent movement of individual body parts
round segments can travel long distances
ankles often detach
flat bones stay closer to point of insertion
Chronological age
birthdays
biological age
growth and development rate
differs from chronological at actual birth
socio-cultural age
sociological markers from progressing through social stages based on your roles and responsibilities
trajectory effect
dissociation of biological age and chronological age
nutritional defects
fetal bone growth
starts at 8 weeks, birth occurs at 40 weeks
juvenile bone growth
in-utero to 5 years: very rapid (triples in size)
5 to puberty: gradual plateau
14-16: spikes again
individual and sex dependent
prenatal
conception to birth
embryo: 1-10 weeks
fetus: 10 weeks to birth
birth: 40 weeks, skeleton formed at 32 weeks
infancy
when baby is nursing
perinate: time of birth
neonate: first 4 weeks after birth
infant: birth to 1 year
childhood
weaning (2-5) to puberty
early childhood: 1-4 years
late childhood: 5-10 years
adolescence
puberty to end of growth
early: 11-14 years
late: 15-17 years
ageing using long bone length
lengths can estimate how long child has been in utero
varies between people because no everyone is the same
standard error
accounts for differences in bone length between each person
ageing using the skull
Sphenoid and mastoid fontanelle: after birth
Posterior fontanelle: 6 months
Anterior fontanelle: 1-2 years
Metopic suture: 2-4 years
ageing using vertebral arches
2 years: neural arches fuse together 3-4 years: pedicals fuse to neural arches
ageing using sacrum
2-6 years: neural arches fuse 12-14 years: lateral element fuses 12-25+ years: sacral vertebrae fusees
ageing using scapula
18-20 years: acromion process fuses 16-17 years: coracoid process fuses 15-20 years: rim of glenoid fossa fuses
ageing using humerus
14-21 years: hemeral head fuses (F=14-19, M=16-21) 11-18 years: distal epiphysis fuses (F=11-15, M=14-18) 13-18 years: medial epiphysis fuses (F=13-15, M=16-18)
ageing using radius
11-17 years: radial head fusing (F=11-13, M=14-17) 14-20 years: distal epiphysis fusing (F=14-17, M=16-20)
ageing using ulna
12-16 years: olcranon fuses (F=12-14, M=13-16) 15-20 years: ulnar head fuses (F=15-17, M=17-20)
ageing using hand and wrist
ageing using femur
12-19 years: femoral head fusing (F=12-16, M=14-19) 14-18 years: greater trochanter fusing (F=14-16, M=16-18) 16-17 years: lesser trochanter fusing 14-18 years: distal epiphysis (F=14-18, M=16-20)
ageing using tibia
13-19: tibial plateau fusing (F=13-17, M=15-19) 14-19: distal epiphysis fusing (F=14-16, M=15-18)
ageing using patella
appears at 3-6 years
ageing using fibula
12-20 years: proximal epiphysis fusing (F=12-17, M=15-20) 12-18 years: distal epiphysis fusing (F=12-15, M=15-18)
ageing using foot
ageing using teeth
ex. M1 Tooth: 1/4 length grown = 4.9 years
ex. I1 Tooth: 1/4 length grown = 4.8 years
tooth eruption
adult or deciduous teeth as they are being exposed through gum line
adult age
young adult: 20-35 years
middle age: 35-50 years
old adult: 50+ years
bones that fuse in adulthood
clavicle: 16-30 years (manubrium end)
sternum: 40 years (xiphoid process, sternal body)
sacrum: 25 years (sacral element 1-2)
os coxa: 27 years (pubic symphysis), 17-23 (iliac crest)
adult bones breaking down
pubic bone - pubic symphysis, auricular surface (gets more holey, coarser, striations, more stable joint)
ilium
ribs - surface bone, surface contour, rim contour
cranial sutures (fill with bone)
pubic symphysis degradation
rib degradation
primary sex characteristics
genitals
secondary sex characteristics
skeletal and phenotypic forms that develop during puberty
female secondary sex characteristics
mechanisms necessary for childbirth
juvenile growth rate faster
male secondary sex characteristics
taller on average
muscle attachments larger
estimating sex
more sexually monomorphic than other species
pelvis: correct 90-95% of the time
skull: correct 80-90% of the time
long bones: correct <80% of the time
sex estimate with nuchal area
m: rugged, may have hook f: smoother, rarely have hook
sex estimate with mastoid process
m: large, projecting f: small, non-projecting
sex estimate with brow ridges
m: large f: small to none
sex estimate with supraorbital margin
m: rounded f: sharp
sex estimate with mental eminence
m: broad or square f: pointed
discriminant function equation
M1: cranial length M2: cranial breadth M3: bizygomatic diameter M4: mastoid process length
sex estimation using pelvic inlet
M: heart-shaped F: circular/elliptical, parturition scarring
sex estimation using subpubic angle/concavity
M: narrow or V-shaped F: wide or U-shaped
sex estimation using ilium
M: tall, denser F: broad, thinner
sex estimation using pubic bone
M: narrow, rectangular F: broad, square
sex estimation using pre-auricular sulcus
M: absent/poorly developed F: present/well-developed
sex estimation using greater sciatic notch
M: narrow F: wide
sex estimation using coxal bone
ventral arc: M=slight/absent, F=strong
subpubic concavity: M=convex, F=concave
ischiopubic ramus ridge: M=broad/flat, F= narrow/crest-like ridge
three main classifications of ethnicity (problematic)
black, white, asian
nose anthroposcopic traits
root
bridge: how far nose sticks out
spine
shape of lower boarder: edge of nostrils (sharp, flat, or no boarder)
shape of nasal aperture (tall, oval, heart-shaped)
face anthroposcopic traits
face width: narrow or wide
eye orbit: angular, rectangular, rounded
suture anthroposcopic traits
sutures: patterns are complex and unique
post-bregmatic depression (where coronal and sagittal suture meet): not always present
jaw and teeth anthroposcopic traits
jaw shape: parabolic, elliptical, hyperbolic
chin shape: small, large/pointed, blunt,
teeth: crowding, gaps, incisor shapes
Carolus Linneas
created the Homo sapiens classification - white, black, dark, red
Johann Blumenbach
first to use comparative anatomy
5 categories: Mongolian, American, Caucasian, Malayan, Ethiopian
sharp force trauma
wounds left on the bone from bladed instruments
narrow focus, dynamic, slow-speed compressive
sometimes resembles blunt force trauma
SFT cleft
deep/wide v-shaped cut
SFT wastage
removal of bone from inside of cleft
SFT punctures
penetrating wound
captures shape of object
SFT striations
lines etched into bone from passage of blade
parallel to cut mark
perpendicular = chopping motion
SFT incisions
gradually tapered v-shapes
longer than they are wide
wound analysis
Wound Description
placement on skeleton
type of wound
size
Instrument Characteristics
Type
Blade
Direction of Force
Number of Traumatic Events
Sequence of Events
Antemortem Injury
healed sharp force trauma
rounded edges
Blunt Force Trauma
elevated level of impact, not high velocity
characterized by radiating fracture lines
type of instrument influences wound seen
BFT instrument size
focused = smaller objects
diffused = wider objects
BFT shape of instrument
cross-sectional outline
longitudinal configuration
injury mimics shape of object
deformation
inbending and outbending at impact site
elastic bone fracture
incomplete - more resistant to forces, more collagen, most often inward bending
brittle bone fracture
complete fracture - whole sections of bone may fail
weak trabecular bone fracture
incomplete fracture - outer table fail, inner table might not
weak inner table
comminuted fracture - inner table fail, outer may not
depressed skull fractures
break in cranial bone, depression towards brain
spiderweb skull fractures
radiating lines on outbent surface
additional force used
stop at suture or previous radiating line
tend to have bone wedges in-between fractures
skull bone wedges
concentric fracture lines and bone wedges forced inward
hinge skull fractures
incomplete fracture on one side of depression
outward bending not completely separating
face fractures
3 areas (denser to weaker facial sections - buttressing)
alveolar ridge
malar eminences
nasofrontal processes
lefort fractures on the face
LeFort 1: between alveolar and nasofrontal
LeFort 2: between nasofrontal and malar
LeFort 3: below anterior temporal and midfrontal
most frequently occurs in high-speed car accidents or falls, or striking the face directly with a rigid object
cranial vault fractures - 4 areas of buttressing
Midfrontal
Midoccipital
Posterior temoral - mastoid process
Anterior temporal - above sphenoid
ring fractures
falling backwards on hard surface, jumping from large heights and landing on feet
skull base fracture
spine shoved into crania
long bone BFT
complete fractures
bone wedges
parry fractures (when you block trauma with your arm)
wound analysis
Wound description
Placement on skeleton, bones being impacted
Type of fractures
Estimate size of instrument
Estimate shape of instrument
Estimate direction of blows
Estimate force
Estimate number of blows
Flaking on edge of fracture = multiple blows to same area
Estimate sequence of trauma
First blow will have greater range of radiating fracture lines
Fracture line that extends the most without being impeded will be first line
Miscellaneous estimations
Intrinsic factors of bones, combination of tools used, different shaped trauma indicating different weapon areas, health issues
BFT ribs
most common cause of rib fractures
direct pressure on ribs = break
BFT vertebrae
most often caused by car accidents - also assault, hanging injuries, sport injuries
BFT scapula
caused by significant BFT - 75% car accidents
BFT pelvis
uncommon in instance of BFT (8-9%) - often car accidents/being hit by a car
burning - stage 1
pugilistic posture
initial evaporation of moisture in body
heat induced bending of limbs at joints
burning - stage 2
soft tissue modification
flesh chars/splits
hair burns off
expulsion of cooked internal organs
larger muscles take longer to burn off
burning - stage 3
bone modification
collagen chars first
bone reduced to mineral
denser bones take longer to modify
bone burning colour change
Low Temperature (200-700 C): yellow brown to darker yellow brown to black
High Temperature (+800 C): dark grey to lighter grey/blue to white (calcination)
bone burning bone cracking
crescent shaped along diaphysis - transverse cracking on long bones
shape relates to speed bone is drying out
bone burning hydrated bone
longitudinal breaks
Note
Flashcard