1. Osteon Forensics

2. Osteon Review

3. Osteons 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

4. Osteon Cells Osteocytes Osteoblasts Osteoclasts Mature bone cells
Create new bone tissue (osteogenesis)
Mature into osteocytes
Osteoclasts
Responsible for bone decomposition (osteolysis)
Critical for calcium metabolism
mercksource.com

5. Osteocytes
msjensen.cehd.umn.edu

6. Osteoblasts
mhhe.com

7. Osteoclasts
orthobullets.com

8. So why are osteons so important in forensics?

9. Forensic Anthropology
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:
Age
Gender
Race
Diet
Disease
Ancestry
Habits
Cause of Death (with help of Forensic Pathologist)

10. Forensic Anthropology
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

11. Human vs. Non-human
vq.vassar.edu

12. Markings
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

13. Size Matters 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

14. Shape
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

15. 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.

16. 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.
engin.umich.edu
Aug_23_2009.pdf

17. 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.
bioone.org
Aug_23_2009.pdf

18. Age
fx.damasgate.com

19. 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 pre-adolescents however can be used for adults.
retsmedicin.ku.dk

20. Cranial Fusion
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

21. 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.
ccd4kids.com

22. 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.
emedicine.medscape.com

23. Osteon Counting
ispub.com
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.
tmj.ro

24. Gender
student.biology.arizona.edu

25. Fundamental Differences Pre-tense
As similar to other sections in this lecture, size & shape become the defining criteria when taking a macro-examinational approach to the determination between the male & female skeleton.
We can natural assume that because of inherent physical capabilities or necessities between males & females that individual bones have acclimated to meet these needs.

26. Cranium or Skull Overall Skull Size Forehead Large in males
Medium in females
Forehead
Low & sloped backwards in males
High & rounded in females
hippie.nu

27. Cranium or Skull Mastoid Process Mandible Very pronounced in males
Diminished or absent in females
Mandible
Close to a 90° angle in males
At an obtuse angle or >90° in females
hippie.nu

28. Pelvis Pelvic opening Sacrum Pubic Symphysis Narrow & linear in males
Wide & circular in females
Sacrum
Equal length & width, turned inwards in males
Short & wide, turned outwards in females
Pubic Symphysis
More pronounced, almost at a 90° angle in males
Less pronounced, almost linear or >90° in females
daviddarling.info

29. 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.
kvitters.com

30. Race or Ethnicity
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

31. Bone structure again…
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:
Caucasoid (European descent)
Mongoloid (Asian descent)
Negroid (African descent)
dodona.proboards.com
s1.zetaboards.com
s1.zetaboards.com

32. Ethnicity Features Eye orbitals Nasal cavity Oval in caucasoid
Circular in mongoloid
Square in negroid
Nasal cavity
Long & narrow in caucasoid
Small & rounded in mongoloid
Wide in negroid
tomorrowstheme.blogspot.com
thebitchtroll.com

33. Ethnicity Features Incisors (teeth) Frontal Plane (cranium)
Smooth in caucasoid
Shoveled interior in mongoloid
Smooth in negroid
Frontal Plane (cranium)
Flat in caucasoid
Flat or projected outward in mongoloid
Projected outward in negroid
freakygaming.com
flickr.com

34. 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.
stanfordmedstudent.blogspot.com

35. The Big Picture
players24.blogspot.com

36. 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?