Forensic Anthropology: How Old is Too Old?

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I recently posted an overview of forensic anthropology.  In the comments, my blogging friend G'Eagle asked how old remains could be before they were too old.

One the tremendous things about forensic anthropology is that it lasts as long as the bones do.  Bones do decompose, and they subject to weathering and damage after death, but they do last a very long time, and as long as there is bone material left, there is some how for forensic anthropologists to be able to recover useful information.

Photo by 120

Biorachaeologists specialize in the excavation and analysis of historic or prehistoric human remains.  They use many of the same techniques that forensic anthropologists use to get at much the same information.  They use these techniques to examine radiographic images of Egyptian mummies, and have been able to recreate the likely scenario of murder of the famous Oetzi the iceman from 5,300 years ago. I have personally determined the age, sex, and some health history of individuals whose remains were 3,000 years old.  I have also been able to say something about peri-mortem wounds on skulls that age.

Forensic anthropologists work in the context of criminal investigations, so they're not worrying about remains that are that old, but this does suggest that, however old the bones are, the age of the bones is not necessarily a concern for forensic anthropology.

That said, completeness and preservation are important.  The more skeletal material is present to be analyzed, the greater the likelihood that an anthropologist will be able to recover useful information.  The better preserved the bones, the more accurate and precise that information will be.  Time itself may not be an enemy, but time does increase the odds of remains being subject to other destructive forces:

• Water
• Bacteria
• Crushing
• Cracking
• Sun
• Fire
• Gnawing by rodest
• Etching by roots
• and so many more

A dry environment that shelters the remains will preserve bones for a considerable time.  As soft tissue mummifies (which can happen naturally) this can help provide a leathery, protective casing for the bones that further shields them from damage.  The more moisture, animals, and open environment remains are exposed to, the more likely that bones will be scattered, damaged, or completely destroyed.

Since forensic anthropology usually works hand-in-hand with law enforcement, it is very often the context of the case which determines how old is too old.  One case I worked, we had a skull and some scattered other remains, and it was enough to show consistency with presumed identity of the victim and to piece together perimortem damage on a serial killer victim from twenty years previous.  

A couple other cases, we had remains that were less than a year old.  One victim was in a dry environment with little stress, and we were able to recover almost every bone and they were all in good shape.  Another victim was in a wet, highly organic environment, and most of the skeletal material was already badly damaged.  However, because of the legal context of the two cases, all they really needed from us was confirmation that the remains could be of a certain basic demographic, and we were able to provide law enforcement that information.

Any other questions?

.Nevets.

Top Ten Things You Never Knew About Forensic Anthropology

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Anthropology lab at the Smithsonian

Most of you know by now that part of my background is in forensic anthropology.  I get the sense, however, that many of you don't quite know what that means, apart from what you may have gathered from the TV show Bones or the novels of forensic anthropologist Kathy Reichs.  I enjoy both of those a great deal, but I think it would be helpful to give you all a little bit of a low down on forensic anthropology, without the lipstick and adrenaline.

First, a quick summary description: forensic anthropologists work with human remains in a medico-legal context.   They typically work with remains with no soft tissue or where the soft tissue is so decomposed that features of the flesh are no longer recognizable.  In other words, forensic anthropologists look at bones, teeth, and the other hard tissues of the human body in the context of a criminal investigation.  Primarily, they assist in the identification of remains and with details of injury, pathology, and sometimes the circumstances surrounding the death of the individual.

So, with that in mind...

The Top Ten Things You Never Knew About Forensic Anthropology

1. One of the most common duties of people who work in forensic anthropology is often simply to assist the police in collecting skeletal remains from crime scenes.  Police are often not trained in the recognition of human hones, nor in the best practices for handling those remains.
2. Before bones can be examined or analyzed, the remains must almost always be macerated or boiled to remove flesh and connective tissue that clings to the bones and obscures important features. Yes, it smells as bad as you probably think it does.
3. Forensic anthropologists officially gives ranges and likelihoods.  Remains are consistent with those of a white male in this thirties, probably about 6'1".  Even when they do a facial reconstruction, it's not for the purposes of positive identification.  
4. Looking at just the bones, you can often tell a lot of detail about an injury -- the entrance and exit of a bullet, the first place that someone was struck by an object, whether damage to a bone was an antemortem (before death) injury or the result of postmortem (after death) activity.
5. The closest forensic anthropologists get to positive identification is in comparing recent injuries to x-rays or (far, far, far more common) in comparing the teeth of the deceased to dental x-rays or records.
6. There are a lot of circumstances that can naturally mummify a corpse.  One of the most tedious tasks facing a forensic anthropologist can be the removal of dried, leathery flesh in order to see the features of the underlying bone.
7. It is very possible to look at a skull and tell with a high degree of certainty whether the person was male or female, get a good approximation of age, and often to suggest the ancestral population ("race") of a person.
8. Maggots are bad.  Cheese skippers are the worst.  Don't Google it if you don't want to know.
9. No guns, no badges, no police cars.  Just labs, calipers, and a twisted sense of humor.
10. Forensic anthropologists do not and may not attest to the cause of death.  They may describe injuries that that occur perimortem (roughly around the time of death) but only a coroner can conclude as to the actual, legal cause of death.

I'd like to continue to introduce you all to this, one of my most dearly beloved fields of study.  If there's anything specific you'd like to hear more about in future posts, please let me know.  I hope this top ten ten list was enough to get your mind going!

.Nevets.