The tickle of curiosity. The gasp of discovery. Fingers running across the keyboard.

The tickle of curiosity. The gasp of discovery. Fingers running across a keyboard

Friday, December 6, 2013

Skeletons in Her closet: The Forensics of Skeletons for Writers



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I curled up like a cat on Miriam’s living room couch with a cup of hibiscus tea steeping on the table beside me. Miriam was on the phone with the police, jotting notes about a case they wanted her to work for them. Someone’s Great Dane came home this morning with a human skull in his mouth. The detective needed a jump-start – some information to get going with while the skull waited its turn on the forensics lab shelf. ~ WEAKEST LYNX










Writers, if your crime scene includes skeletal remains or even remains that have advanced to a soupy mess, the person who is called in to take control of the bones is a FORENSIC ANTHROPOLOGIST.
***NOTE: The forensic anthropologist is applying their post graduate studies in biology and anatomy as well as their understanding of trauma to research the bones. They do not solve the crime. They do not interview suspects or witnesses (LINK to Interrogation for Writers). They simply: study, document, report, testify (where necessary).


Forensic anthropologists can help identify ske...
Forensic anthropologists can help identify skeletonized human remains, such as these found lying in scrub in Western Australia, circa 1900–1910. (Photo credit: Wikipedia)



Forensic Anthropology - Dem Bones!
Video Quick Study (3:13) Tanya Peckmann talks about her job.

Servicemembers search for POW/MIAs on Wake Isl...
Servicemembers search for POW/MIAs on Wake Island Greg Berg uses a sifter to look for bone and artifacts at a dig site Jan. 12 on Wake Island. Mr. Berg, a forensic anthropologist, was sent to do a site survey after Wake Island officials notified the Joint POW/MIA Accounting Command of bones located on the island. JPAC officials are charged with achieving the fullest possible accounting of all Americans missing as a result of past conflicts. (U.S. Air Force photo/Tech. Sgt. Shane A. Cuomo) (Photo credit: Wikipedia)
The job of Forensic Anthropologists is to make some determinations concerning the skeleton that was discovered or exhumed. They are called in by officials to remove the remains.
* Remains are placed in a body bag for transport to a
   forensic laboratory.
* The remains are reconfigured to a supine position, and
   photographed.
* Any remaining soft tissue is cut away from the skeleton
* The bones are abraded with steel wool to remove dirt,
   bugs, and soft tissues.
* The bones are then soaked in a chemical solution to
    further clean and prepare them for examination.

This Video Quick Study (12:04) is a non-narrated look at a forensic anthropologist team at work





The Forensic Anthropologists attempt to make the first sets of identifying data:
* Approximate age
FAFG - coded corpse
FAFG - coded corpse (Photo credit: xeni)
* Sex
* Size/height
* Ancestry


AGE:


* Teeth and bone growth help to identify the proper age.
* Precise age determination is easier in children than in adults because of the statistical probability of various
   developments taking place in teeth and bone fusion/growth plates.
* Age results for adult remains are given in broad ranges.
* 206 is the average number of bones of an adult.
* An adult  skull has approximately 22 bones.
Parts of a long bone
Parts of a long bone (Photo credit: Wikipedia)
* A newborn skull has approximately 44 bones.
* In assessing age in children, the long bones of the body
   show dramatic changes with age.
*ossification of the growth plates follow general
  standards:
  - First growth plates close at the elbow
  - next ankles, knees, hips, then shoulders.
  -  The last growth plate to close up is the central tip of
     the clavicle around 23-28. (health and nutrition
     effects this age span)

Video Quick Study (1:48) - bone changes from infancy to adult

   * Teeth form from crown to root.
   * At birth primary teeth are already present in the jaw.
   * At 6 mos most infants have visible teeth.

Video Quick Study (3:17) Dr. Snow identifies Gacy's
                                        victims by age.


English: diagram of a human female skeleton, b...
. (Photo credit: Wikipedia)

SEX:

* Prior to puberty, the skeletal remains cannot
   be identified as male or female without DNA.
* A pelvis in a female is wider from front to back.
* Joints tend to be larger on males.

THE SKULL - this information is statistically correct. Measurements are made and compared at different points on the skull to determine a statistical probability rather than a 100% certainty.
* Male occipital protuberance is larger to attach larger
   neck muscles.
* Male brow ridges are larger
* Women tend to have higher smoother foreheads.
* Male jaws tend to be at a 90 degree angle with
   squared corners.
* Women's jaws tend to be smoother with
   pointier chins

Video Quick Study (2:35)





the adult skull is normally made up of 22 bone...
the adult skull is normally made up of 22 bones. Except for the mandible, all of the bones of the skull are joined together by sutures, semi-rigid articulations formed by bony ossification, the presence of Sharpey's fibres permitting a little flexibility (Photo credit: Wikipedia)

SIZE AND HEIGHT


* Is best identified from a full skeleton.
* Statistics have been developed to allow a range based on skull size.

the adult skull is normally made up of 22 bone...
the adult skull is normally made up of 22 bones. Except for the mandible, all of the bones of the skull are joined together by sutures, semi-rigid articulations formed by bony ossification, the presence of Sharpey's fibres permitting a little flexibility (Photo credit: Wikipedia)

ANCESTRY

* Without DNA ancestry is difficult.
   LINK to DNA article
* DNA is best harvested from the teeth, though it is
   possible to extract from bone.
* Skull structure yields the biggest clues about
   race/ancestry based on math formulas.
* Few people today come from a racially pure
   ancestral line, making identification more difficult.
* In order to apply the statistics to ancestral
   identification, a fairly intact skull is required.


Skeletons under excavation at Walkington Wold
Skeletons under excavation at Walkington Wold (Photo credit: Wikipedia)

Beyond excavation (LINK to Crime Scene Info for Writers), and the preliminaries of age, sex, size and ancestry, a forensic anthropologist can offer investigators other identifying information:
* History of bone breakage
* History of surgical interventions such as ACL replacements and other injuries where screws and implants
   were used.
* Nutrition over the life span
* Toxicity over time such as arsenic or mercury.
* Exposure to heavy metals like lead

* They can also help determine the number of skeletons in a mass destruction such as a large fire or plane
   accident.

They can inform and testify about stab wounds and what type of weapon might have been used through trauma analysis.
* Was the break:
   - antemortim trauma - before death like healed fracture or screws from surgical repair.
   - post mortem trauma - what happened to skeleton after the death - like an animal
   - perimortem trauma - bone damage at or around the time of death, such as  a broken jaw or cracked
     skull.

To gather this information they use CAT scans, and other medical diagnostic machinery.
Video Quick Study (3:51) Discusses high-tech tools.





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13 comments:

  1. Another fine article, Fiona! I wonder if the surgery and hormone treatments for transgenders make skeletal identification difficult?
    Forensic anthropology may be very interesting, but it's not going to be for the squeamish!

    I hope this works, I've never been able to leave a comment on your page for some reason.

    ReplyDelete
    Replies
    1. Andrea,

      First, I apologize for any trouble you were having leaving messages. Thanks for trying again! I can't account for it :(

      Typically the hormonal therapy happens post skeletal development. The joint size, occipital bulb, jaw line, chin etc. would be formed prior to intervention (at the first signs of pubescence). Plastic surgery to address cosmetic changes would be visible. And too, there would be no change to the pelvic girdle. So I would say even if a male or female has done a full gender reassignment, the skeleton would remain unchanged. DNA would come up as either xx or xy.

      Great question! Cheers
      ~Fiona

      Delete
    2. Fiona, when I try with Firefox, it doesn't work, but IE does, so apparently it's a compatibility issue.

      I read an article recently about an East German Olympic athlete that was, without her knowledge, given so many hormones that she had to change sex, and now certainly looks male. As these hormones were administered while she was in her early teens, if memory serves, it may have altered the skeleton enough for confident misidentification, but the DNA, as you state, would presumably still say xx. If they did the DNA test, it would say xx, but they would be looking for someone who had lived adult life as a male...plot twist!

      Delete
    3. Hey Andrea,

      Thanks for hanging in there and trying again. I'm not sure how to fix this glitch but will do my best - and if any of my readers want to chime in, please do.

      About the athlete, I believe you are referring to Heidi Kreiger. The East Germans were - unbeknownst to their female athletes who thought they were receiving vitamin shots - giving their young athletes hormonal therapies. This resulted in clitoral enlargement, chest hair, acne, messed up menstrual cycles, as well as subtle changes in their appearance. According to Dash (below), bones are particularly receptive to testosterone, so I would imagine this meant that their bones thickened and strengthened and their joints were enlarged. Heidi Kreiger went on to have gender reassignment surgery and is now Andreas Kreiger. She (now he) competed at a time when DNA testing was not available. Those who doped the team were jailed.

      More recently is the case of Caster Semenya. While visually a female, with female genitalia, she was in the news because the Olympic Committee was looking into her sex (gender being a choice/social construct). First, they needed to debate the criteria for assigning a sex. Personally, I would think DNA would be a straight forward test. Apparently, they decided that it depended on testosterone production.

      It was found that Semanya had characteristics of both males and females and produced significantly more testosterone than a female. As of 2012 when the linked article was written, Semenya was being medically treated to allow her to compete in future athletic events. (http://www.thedailybeast.com/articles/2012/07/26/caster-semenya-and-the-ioc-s-olympics-gender-bender.html)

      Definitely plot twist material here!!!!
      Cheers, and thanks for adding a great new angle!
      ~ Fiona

      Delete
  2. Excellent article. This is my current area of study, so of course I was interested. You have a lot of good info compiled here, a few things I'd like to add.
    Pelvis is the most accurate bone for sex determination (~90-100% versus ~80-90% on skull), if you got both pelvis and skull, you're pretty much looking at 100% accuracy. Main features that a physical anthropologist would look at is shape of sub-pubic angle, width of greater sciatic notch, and the medial curvature (where the two pubic bones articulate with the sacrum). Coincidentally, sacrum is another bone that might be used in sex determination (based on it's curvature) others include sternum and femur, but are far less accurate and less preferred to skull and pelvis. Also note that if all of these bones are present, the physical anthropologist would use all of them, and not just base her determination off of one.
    Advanced age can also effect sex determination, particularly in female skulls. Your skeleton continues to change throughout your life course, it never remains stagnant, and bone cells can be reorganized to suit immediate needs. One thing that can affect it is definitely hormone levels. Post-menopausal women, for example, tend to have higher levels of testosterone which begins to masculinize the bone. Bones really like hormones, it spurs them to grow, but they love testosterone most; so you might see less affect on a M to F versus a F to M transgendered individual, don't know for certain. It would really be an interesting study to see long term effects of hormone treatment on an adult skeleton.
    Which does come to a very interesting point, that ties into ancestry as well. There is a difference between the identification a physical anthropologist might get from the skeleton and the way a person identified in life. Its important to remember that the physical anthropologist is not the one that will be searching out a skeleton's actual identification, they're just giving the police a few search parameters. If they give the police the wrong parameters, for instance, give a male sex identification to an individual that lived life as a woman, that could complicate, if not make completely impossible, the police efforts to ID the deceased. Going back to ancestry, what police actually want in this regards, is race. Race is a social construct, it doesn't have biological determinants. There are "races" constructed around groups of people who originate from particular regions, some traits may be predominant to that region, but aren't exclusive to that region and there is always wide variation even in a cultural group. Going back to identification, an individual may have identified with one race, but the anthropologist might link the skeletal traits to another race, which would of course, hinder the investigation. Sometimes it's better for the anthropologist to just say "I don't know" rather than give a bad identification. DNA tests aren't always done, they can be kind of expensive and not always in the police budget.
    A last note, writers that want to incorporate forensic anthropology into their story should familiarize themselves with the concepts of "manner of death" and "cause of death". A physical anthropologist can suggest manner of death (ie. murder, or natural), but is never the one to determine cause of death. Coroner or medical examiner determines cause of death, and they also lead the investigation on the skeleton, not the anthropologist.

    Once again, great post! Very informative. Would love to see a follow up on the effects of fire on bone, or even just violence that can be seen on bones. Also, forensic entomology would be interesting too.

    ReplyDelete
    Replies
    1. Dash,

      Thank you so much for adding this information. I really appreciate you taking the time.
      I have a blog article on entomology in process; look for it in a couple of weeks. The effects of violence and fire would make a great article. Is this an expertise for you? Would you interested in my interviewing you? If not, I will find someone to speak with because this is not my bailiwick. (You can message me on FB fionaquinnbooks)

      Cheers!
      ~Fiona

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  3. Fascinating article and a great resource. Thanks!

    ReplyDelete
  4. My pleasure. Thank you kindly.

    ReplyDelete
  5. Great article! So much info I can sink my teeth into. I tweeted and will plug this article on my blog on Fri. Thanks! :)

    ReplyDelete
    Replies
    1. Thanks for your support, Lexa :)

      Cheers,
      Fiona

      Delete
  6. I wanted to confirm something...is it true that a coroner can determine strangulation as a cause of death due to the broken hyoid (sp?) bone in the cervical spine/neck area?

    ReplyDelete
    Replies
    1. Let me ask a medical examiner. I'll get back to you when she answers.

      Delete
    2. Judy Melinek says:
      Not exactly. I've seen broken hyoid bones from falls down stairs and motor vehicles that run over the neck. It depends on the circumstances and other findings. Typically strangulations also have front neck muscle hemorrhages and petechiae (pin point burst blood vessels) in the whites of the eyes and inner eyelids. Hope this helps

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