Transcript Osteon Forensics

Osteons
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Osteons are the basic
functional unit of
compact bone.
Osteons are made of
many concentric
lamellae (layers) that
are similar to rings of
a tree.
These layers are
made of mainly
osteocytes (bone
generating cells) and
branch out from the
central canal.
feppd.org
Osteon Cells

Osteocytes
 Mature bone cells
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Osteoblasts
 Create new bone
tissue
(osteogenesis)
 Mature into
osteocytes
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Osteoclasts
 Responsible for
bone decomposition
(osteolysis)
 Critical for calcium
metabolism
mercksource.com
Osteocytes
msjensen.cehd.umn.edu
Osteoblasts
mhhe.com
Osteoclasts
orthobullets.com
Forensic Anthropology
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The combination of physical anthropology and
osteology(study of human bones).
Usually work with human remains that have
undergone many cycles of decomposition.
Utilize macro or micro(osteon) examinations
Can help determine:
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Age
Gender
Race
Diet
Disease
Ancestry
Habits
Cause of Death (with help of Forensic Pathologist)
Forensic Anthropology
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We will take a look at how a Forensic
Anthropologist (FA) determines the
following from macro & micro
examinations:
 Human vs. Non-human remains
 Age
 Gender
 Race
vq.vassar.edu
Markings
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Most human bones,
especially the larger,
have several markers
that make them easily
identifiable.
These series of
markings (notches,
spines, tubercles,
tuberocities, grooves,
condyles, etc.) are
unique in combination
to human bones.
bookdome.com
resendizhumananatomyatlasc.blogspot.com
Size Matters
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Certain human
bones can also be
identified based on
size.
The photo shows
the gradual size
difference between
a human femur(far
right) and other
various mammals.
liebertonline.com
tnhistoryforkids.org
Shape
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Certain bones can
be distinguished
based on their
individual shape.
The photo shows a
cranial comparison
between human and
various primates
(which carry the
closest resemblance
to the human
cranium).
caveman2point0.blogspot.com
In a nutshell…
These three types of
macro-examination can
be utilized individually or
together.
 Some human bones can
not be identified as
human by large-scale
physical examination.
 However, microscopic
examination of osteon
patterns can give results
where macroscopic
examinations leave off.
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Osteon Patterns
One of the first and
major factors that is
observed is the
presence of a type of
laminar bone called
plexiform.
 Plexiform is a highly
organized type of bone
that is necessary in
mammals that undergo
a rapid growth cycle.
 The significance is that
this type of bone pattern
is rarely found in human
bones.
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engin.umich.edu
www.cas.umt.edu/.../06_What_Remains_Robbins_et_al_ANTH_OF_DESP_ Aug_23_2009.pdf
More patterns…
In addition to
plexiform presence
the organization of
primary & secondary
osteons also help in
determination.
 Primary osteons
occasionally occur in
small regions in
human bones.
 Secondary osteons
are quite common in
humans.
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bioone.org
www.cas.umt.edu/.../06_What_Remains_Robbins_et_al_ANTH_OF_DESP_ Aug_23_2009.pdf
fx.damasgate.com
Length of long bones…
One method used for
determining age is the
length of certain long
bones (femur &
humerus).
 The measurement of the
long bone is compared
to standard examples at
specific ages.
 This primarily applies to
children and preadolescents however
can be used for adults.
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retsmedicin.ku.dk
Cranial Fusion
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The fusing of the flat
bones of the
cranium can also
determine an
estimation of age.
Similar to the
estimation using
long bones, the
fissures of the skull
disappear at specific
ages of
development.
flickr.com
Dental Growth
Dental growth is
another method, when
compared to standard
development scales,
that can determine
approximate age.
 This method is more
useful in infants &
children since a
majority of
development occurs
during the earlier
years of the human
lifecycle.
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ccd4kids.com
Are you worn out yet?
A change to the surface of
certain bones, bone wearing
or erosion, can also
contribute to age
determination especially in
adults.
 Standards of bone erosion
are compared to bones that
undergo common wear such
as the pubic symphysis.
 The pubic symphysis goes
from having a rough, rugged
surface to a smooth area over
time.
 The downside of this is that
FA are measuring the
degradation of bones which is
more variable to error due to
other factors.
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emedicine.medscape.com
Osteon Counting
Coming out of the
developmental and
testing phases of
research.
 Several studies have
been able to link the
number of osteons in a
specific area of compact
bone with certain stages
of development in the
human lifecycle.
 This is important
because FA’s don’t
always find bones in
pristine condition.
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ispub.com
tmj.ro
student.biology.arizona.edu
Fundamental Differences Pre-tense
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As similar to other
sections in this
lecture, size &
shape become the
defining criteria
when taking a
macroexaminational
approach to the
determination
between the male &
female skeleton.
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We can natural
assume that
because of inherent
physical capabilities
or necessities
between males &
females that
individual bones
have acclimated to
meet these needs.
Cranium or Skull
Overall Skull
Size
1.
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Large in males
Medium in females
Forehead
2.
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Low & sloped
backwards in
males
High & rounded in
females
hippie.nu
Cranium or Skull
Mastoid Process
3.
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Very pronounced in
males
Diminished or
absent in females
Mandible
4.
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Close to a 90° angle
in males
At an obtuse angle or
>90° in females
hippie.nu
Pelvis
Pelvic opening
1.
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Narrow & linear in males
Wide & circular in females
Sacrum
2.
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Equal length & width,
turned inwards in males
Short & wide, turned
outwards in females
Pubic Symphysis
3.
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More pronounced, almost
at a 90° angle in males
Less pronounced, almost
linear or >90° in females
daviddarling.info
So what about the Osteons?
Believe it or not,
osteons can play an
important role in
determining gender.
 Several studies have
identified that osteon
size can determine
gender.
 Mean osteon size has
been determined to be
approx. .004mm² larger
in males vs. females.
 This research is still in
the initial stages.
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kvitters.com
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Determining race or
ethnicity from
skeletal remains is a
bit more difficult than
gender or age.
This section outlines
the more common
features of
identification.
drsharma.ca
Bone structure again…
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The most common
method for
determining ethnicity
from skeletal remains
is based on several
features of the
cranium or skull.
Three main categories
are defined:
dodona.proboards.com
 Caucasoid (European
descent)
 Mongoloid (Asian
descent)
 Negroid (African
descent)
s1.zetaboards.com
s1.zetaboards.com
Ethnicity Features
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Eye orbitals
 Oval in caucasoid
 Circular in mongoloid
 Square in negroid
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Nasal cavity
 Long & narrow in
tomorrowstheme.blogspot.com
caucasoid
 Small & rounded in
mongoloid
 Wide in negroid
thebitchtroll.com
Ethnicity Features
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Incisors (teeth)
 Smooth in caucasoid
 Shoveled interior in
mongoloid
 Smooth in negroid
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Frontal Plane
(cranium)
freakygaming.com
 Flat in caucasoid
 Flat or projected
outward in mongoloid
 Projected outward in
negroid
flickr.com
Osteons again…
Similarly with determining
age, osteon counting is
also useful in determining
ethnicity.
 This determination is
based on several factors
including size, density, &
quantity.
 As with most osteon
determining research,
this type is relatively in
the earliest phases.
 No concrete theories
have yet to be proven
valid.
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stanfordmedstudent.blogspot.com
players24.blogspot.com
What does it all mean?
There are many ways of determining
information about skeletal remains. Most
of them must be utilized in conjunction with
one another and each one has a variably
large margin for error.
 While most osteon determining factors are
in the earlier stages of development, it is
soon to be the most accurate method for
answering the questions that forensic
anthropologists are asking: What can these
bones tell us?
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