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Osteon Forensics

Osteon Forensics. Osteon Review. 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.

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Osteon Forensics

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  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 • Mature bone cells • Osteoblasts • 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 www.cas.umt.edu/.../06_What_Remains_Robbins_et_al_ANTH_OF_DESP_ 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 www.cas.umt.edu/.../06_What_Remains_Robbins_et_al_ANTH_OF_DESP_ 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 • Large in males • Medium in females • Forehead • Low & sloped backwards in males • High & rounded in females hippie.nu

  27. Cranium or Skull • Mastoid Process • 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 • 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 • 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) • 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?

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