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. feppd.org

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

Osteocytes msjensen.cehd.umn.edu

Osteoblasts mhhe.com

Osteoclasts orthobullets.com

So why are osteons so important in forensics?

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)

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

Human vs. Non-human vq.vassar.edu

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

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

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

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.

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

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

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

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

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

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

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

Gender student.biology.arizona.edu

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.

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

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

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

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

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

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

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

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

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

The Big Picture 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?