It’s pretty common to let the flickering blue-light of the television usher us into the autopsy laboratory with a pathologist diligently removing soft tissue samples to be analysed soon afterward. Unless you’re watching BONES, you might never realise that many clever observations regarding the circumstances surrounding an individual’s untimely passing are made by the forensic anthropologists (read: specialists who are committed to studying the human skeletal system, and its embodiment as evidence).
Even after a person becomes unrecognisable and has disintegrated almost fully into the environment which surrounds them, there is a comprehensive discipline which allows us to extract vast amounts of information about them: their sex; age at death; ancestry or race; stature; and even (if facial reconstruction is applied) what they might have looked like. Desperate situations, in which the person cannot be identified in any other way (e.g. the location of personal effects near the body), make anthropology an even more significant tool in homicide investigations.
Clues consolidated in calcium
Aside from evaluating bones for basic features, anthropologists can also construct an accurate picture of what occurred immediately before death — and even reconstruct the cause of death. Here, we’re focused on four inferences that can be made about a person’s death solely from anthropological study.
1. Some sort of mechanical forces were involved.
Mechanical forces can manifest themselves in countless ways on bone — insults look like cut marks, sharp force injuries, blunt force trauma and wounds (many of which will be discussed in further detail below). Still, it’s worth mentioning that anthropologists can differentiate these forces from, say, the impressions on skeletal remains of plane crash victims or fatalities in building explosions.
While we’re alive, bone is actually quite elastic. We don’t think about it as bouncy per se, but if a force is slow to build and doesn’t contain much power, our bones are surprisingly pliable enough to distribute and handle the assault. A great deal of force applied quickly, however, doesn’t give the bone much time to fracture before it has a chance to demonstrate its qualities.
So how do we determine what type of mechanical forces caused the various markings left in human remains? Read on.
2. Blunt force trauma played a role.
This is a phrase we’ve probably heard repeated on television shows one too many times. Still, what does “blunt force trauma” actually mean?
Very simply (and without too much discussion of the physics-y tensile forces it involves), the phrase specifies damage caused to bone by objects with a broad surface rather than a sharp instrument. This type of injury can cause the bone to actually deform — or take on a slightly different shape — before it shatters to pieces.
An anthropologist can identify blunt force trauma by looking for wedge-shaped fragments of bone. They appear like larger triangles which have broken off in chunks and have separated from the rest of the cranium, or another larger and continuous bony surface.
3. Cut marks point to the involvement of potentially lethal objects.
Where no blunt force trauma is evident, you may see cut marks instead. This characteristic cutting pattern can be seen in extremely graphic detail through a scanning electron microscope, which elegantly sweeps across the surface of the bone to show you the swift marks of a blade or another sharp implement. These marks can, of course, be caused by any sharp object which incises the bone.
If you’re looking closely at these marks (like through the lens of the microscope mentioned above) you’ll begin to notice that these cuts have a characteristic “V” shape. To the untrained eye, it’s easy to mix these up with rodent tooth marks (made by animals gnawing on the bones of skeletal remains) — but such impressions are typically paired and have a squarish cross-section.
4. Gunshot wounds may have been CoD or a contributing factor.
The most obvious evidence of any mechanical forces acting on human bone is probably the gunshot wound. To the trained specialist, however, there’s a lot more than can be extracted by careful examination of these remains. Bullets of different sizes (caliber) are projected by a wide range of explosive forces — both of which can be determined by analysing the impact and shape of the shattering on the bone.
It’s a predictable pattern really: a missile usually creates a round opening which is smaller at the initial point of impact and larger at the point of exit. This is one method that is used to pinpoint the direction in which a given bullet travelled — athough the direction of beveling isn’t always accurate.
Your Turn: An experienced forensic anthropologist with years of experience under your belt and an eagerness to share tricks of your trade? An amateur fascinated by what you’ve learned here? No matter who you are, please let us know what you think about this article in the comments.