A Bone to Pick: Basics of Palaeopathology

Palaeopathology is the study of ancient diseases, trauma, disability etc. by examining human remains. Like forensic anthropologists, palaeopathologists also work with a degree of uncertainty. When most of our data comes from the examination of human bones, there are specific limitations we must contend with.

Bone can only react in one of two ways when something is wrong; the bone tissue can either grow or it can resorb. Both bone growth and resorption are normal and happen throughout your life–this process is caused by cells called osteoblasts and osteoclasts–but disease, trauma, and malnutrition can create abnormal formations of bone called lesions. The lesions formed by excess bone growth are called proliferative, and lesions formed from resorption are called lytic.

Each disease will affect bone in slightly different ways, that is if they affect the bone at all. But because of these limited types of bone reaction, certain diseases can look very similar. For example, scurvy and cribra orbitalia are both characterised by lesions in the orbitals (eye sockets) which can be hard to distinguish without training and practice.

Scurvy is a metabolic disease caused by a lack of vitamin C. As our bodies need vitamin C to form collagen, and our blood vessels require collagen for structural stability, the capillaries in the eye sockets of those with scurvy begin to bleed. The presence of blood in the orbit stimulates new bone growth and creates proliferative lesions.

Cribra orbitalia, which is often attributed to iron difficiency anaemia (rightly or wrongly is still up for debate), is charaterised by lytic lesions in the same area.

Below are pictures of both conditions, can you tell which one is which?

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These are excellent examples of each type of lesion, so this is pretty much as easy as it gets. Most presentations of these lesions will be less pronounced, more fragmented, or both. Which makes our job a bit harder.

You can check your answers and access the original images here and here.

Too easy? Let’s try this one:

Do these skulls all feature the same pathology? Or are there two pathologies? Or even three?

What differences in these lesions, if any, can you observe?

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Hint: there are two diseases and one trauma featured above. Can you tell which ones are which?

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The first skull is an example of caries sicca, a major sign of venereal syphilis.

The second skull has a penetrating gunshot wound to the forehead.

And the third skull is an example of lesions associated with calvarial tuberculosis.

We can differentiate all of these conditions by looking at the remodeling (healing) process, or the origin of the lesion–for example, did it start inside the skull and move outwards or start on the surface and move inwards?

Another practical issue palaeopathologists face is something called the osteological paradox.  And while this term seems big and scary it’s actually pretty simple.  In order for a disease to show up in the bone, it has to be around long enough in a living body. We call this kind of disease chronic.  If a disease is too deadly and kills a person quickly, it won’t have time to affect the bone.  We call this kind of disease acute.  Therefore, when we see an individual from an archaeological site with a pathology, we know that actually this individual was probably one of the healthier ones. So ironically, when palaeopathologists study pathology, we’re usually studying the healthier individuals of a community.  This can be problematic when trying to ascertain general health trends and quality of life.

 

If you’re interested in the diagnostic criteria for any specific diseases or want more info about bone biology, keep your eye out for upcoming posts or comment below!

NAGPRA and the Repatriation of Human Remains

Studying human remains can raise some pretty serious ethical questions. The large skeletal collections housed in the United States, like the Terry and Todd collections, are composed largely of dubiously collected remains from all over the world. And while these collections are treated with the utmost respect by researchers, it still does not lessen the damage early archaeological excavations caused the indigenous groups that these remains were taken from. In countries where remains are by and large excavated by archaeologists of the same ethnic heritage–the U.K. and continental Europe mainly–there is an overwhelmingly positive attitude towards excavation and analysis of skeletal remains. However, these areas do not carry the same colonial burden as the United States, where excavations were done without regard to the cultural heritage or the needs of surviving communities.
In 1990, the United States enacted a law called NAGPRA (Native American Graves Protection and Repatriation Act). This requires any institution that receives federal funding to return any cultural items to the descendants of the groups that the items were taken from. This includes human remains.
Museums like the American Museum of Natural History faced a monumental task. Many of these cultural artifacts were kept protected in climate controlled collections, and if they were returned immediately would undoubtedly degrade irreparably. It is standard practice now to return items only when there are suitable facilities to keep the artifacts safe.
AMNH faced another monumental problem. They had built their multimillion dollar Rose Center around the Willamette meteorite .  This meteorite had been taken from a Native American group called the Grand Rhode in 1906. As dissembling the Rose Center would be economically catastrophic for the museum, groups from the Grand Rhode are given complete access annually to the meteorite to perform cultural rites. These ceremonies are not open to the public. Similarly, the Archaeology Department will invite members of Native American groups to come examine the artifacts that are still housed within the museum.
The complexity of this issue this is further examined in this documentary about the repatriation of a totem pole.

In many cases, Native American groups do not necessarily want to take repossession of human remains, as they are kept safe in the museum, but do not want the remains to be used for research. The Biological Anthropology Department honours this desire.

Do you have any questions regarding the ethical excavation of human remains? Ask away in the comments section or on the contact page!

 

Biological Anthropology – An Overview

Biological anthropology is one of the four major subfields of anthropology. Very generally, biological anthropology examines the biological development of human beings–meaning that we study everything from human evolution, our evolutionary cousins (other primates), comparative anatomy, osteology (the study of bones), and ecology.

Here are just some of the many subfields of biological anthropology:

Palaeoanthropology – the study of human evolution and diversity
Primatology – the study of nonhuman primates
Forensic Anthropology – the use of human osteology in a legal context
Bioarchaeology – the study of human remains from archaeological sites
Human Ecology – the study of human interaction with the environment

All of these subjects seek to shed light on our history as organisms, but they also have direct and practical relevance to our world today. A major aspect of primatology, for example, is primate conservation. And forensic anthropology is used all over the world by police departments, major investigative parties after war, and in the wake of mass casualty events such as terrorism or natural disaster.
Very often, the practical subfields of biological anthropology are considered ‘anthropology’s jock-y younger brothers’ because we lack the theoretical framework that social anthropology and archaeology have in spades. But more on that later.

For everybody in New York City (my hometown), there’s a fantastic permanent exhibit at the American Museum of Natural History called the Hall of Human Origins. It gives the lowdown on all of the major themes of biological anthropology and its many subfields. Also worth looking at is the Hall of Primates for just a small taste of the enormous diversity found in our taxonomical order.

It also provides an opportunity to compare your body to those of other apes!amnh

Notice the similar brachial morphology between the human and the orangutan!

 

On a solemn note:

Anthropology as a whole had a considerable role in proliferation of racist tropes in the late 19th century and well into the 20th. But biological anthropology’s involvement in the proliferation of these tropes is arguably the most sordid. Because we were able to mask our racial bias in the cloak of science, our research into the different ‘races’ of humans could be used as ‘proof’ of white and male supremacy. I put the word race in quotations because in the world of biology race literally means species! Anthropologists had a hand in creating this narrative. One particularly infamous study measured the cranial capacity of different races with the intention of proving that white people had bigger brains and were therefore smarter. This is, of course, bad science and there remains no relationship between brain size and intelligence anyway. When anthropologists began examining human evolution, their research was used to ‘prove’ that people of colour were less evolved and therefore more closely related to other primates than white people were. And these stereotypes have managed to stick around until today! There is also evidence that members of the Nazi Party utilised the same osteological collections that anthropologists rely on today to search for observable differences in the skeleton based on race. So it is critical that biological anthropologists acknowledge their discipline’s history and stand in staunch academic opposition to its lingering effects.

Have any questions about biological anthropology? As always, feel free to leave a comment or message me on the contact page.

The Evolution Debate

Another subfield of biological anthropology that I’ve worked in is palaeoanthropology. Which, very simply, is the study of human evolution.

And one of the most frustrating things I’ve experienced as an anthropologist is not evolution denial, but the very clear inability of people who do believe in evolution to give good answers to the questions put to them by those evolution deniers. I’ve seen Bill Maher laugh off a question posed by Michelle Bachmann about evolution, not because it was too ridiculous to acknowledge but because he didn’t know the answer.  Even people like Bill Nye have trouble articulating answers in an accessible way.  

Evolution has become a dirty word.  Most people who aren’t convinced by evolution have no problem believing in other things that are dependent on evolution. 

If you believe in the flu vaccine, you believe in evolution.

If you believe in DNA, you believe in evolution.

And if you believe that the rhinoceros is almost extinct, then you also believe in evolution. 

I’ll explain.

We know that animals don’t just go extinct for no reason, something always happens to drive that animal to extinction — like drought or overhunting. Another term for that something is pressure. So the pressure for the rhino in this hypothetical scenario could be poachers who take their horns.

We also know that while some animals are on the verge of extinction, other animals are not. This means some animals aren’t affected by this particular pressure like the rhinos. If poachers don’t bother with hippos because they don’t have horns, hippos will last longer than rhinos. 

Recap: some animals can survive more easily in an environment than others.

Most people can accept this, so let’s continue.  

If a rhino was born without a horn, poachers would have no interest in it and leave it alone. Then that rhino could go off and have hornless babies which the poachers would have no interest in either.  Now suddenly, you have a bunch of hornless rhinos happily hanging around while the rhinos with horns dwindle.  

There you go. That’s it. This is all that Darwin was describing (except with birds) and it’s called selection. 

An animal is born with a mutation, like a bird with a strange beak or a rhino without a horn. When this mutation is useful, like it makes it easier to find food or it makes you unattractive to poachers, then that animal can live longer and have more babies who then might also have this mutation.  These useful mutations are called adaptations. 

And there are different types of selection. When the pressure is environmental, we call it natural selection. When humans breed plants or animals for certain traits, it’s called artificial selection. 

Darwin had no sense of how these mutations happened or were passed on, but we do!  When we discovered DNA, everything really fell into place.  We could see that all of our traits were written in our genetics and could be passed down to our children.

The most stunning example of this selection process can be seen (yes actually seen!) when tracking antibiotic resistant bacteria. Please go watch this clip.  

The antibiotic is the pressure, like the poacher to the rhino, and we can see where and when the bacteria mutate, like the hornless rhino.  Flu vaccines get updated every year because the virus adapts very quickly, much in the same way the E. coli adapts in this video.  

Now how does all of this translate to the bigger picture? 

The more rhino babies born without horns, and the more poachers kill rhinos with horns, the more likely it becomes for hornless rhinos to end up mating with other hornless rhinos, as they survive better. If we were to fast forward a million years, the hornless gene could become so separated from the horn gene that if a hornless rhino were to come across a horned rhino and mate, they either would have a sterile baby or no baby at all.  This is called speciation.

These new species will face other pressures, adapt, and maybe speciate again! And this goes on and on and on until the world ends. Which is why we have such a wonderfully diverse world.  All it would take to create the world we see today is one microbe in the right conditions and time. Reproduction, mutation, and adaptation have been happening every single second of every single day for millions and millions of years.

Some common questions/statements I’ve encountered:

Michelle Bachman’s question mentioned above was ‘why are there still monkeys if humans evolved from them?’ 

Good question, Michelle! The monkeys we evolved from existed millions and millions of years ago. We did not evolve from current species of monkey.  We are evolutionary cousins, if you will, with current monkeys because we share what’s called a common ancestor. Say there was another rhino who was born with a mutation that gave it camouflage to hide from poachers. Then it went through the same selection process as the hornless rhino to become its own species.  The hornless rhino and this camouflage rhino would share a common ancestor.   

Another common question is ‘where is the missing link?’ 

Well get ready to have your mind blown.  There is no missing link and there has never been.  We have found numerous remains of our evolutionary ancestors! Each species we’ve identified has multiple samples associated with it.  Before Darwin was even on the scene, neanderthal remains had been discovered!  So never from the inception of evolution as a concept has there been a missing link.

A common misconception is that ‘Lucy,’ the Australopithecus afarensis skeleton from Ethiopia, is the only sample we have. This could not be less true. Lucy is just one great example of many from that particular species.

‘Link’ is also an inappropriate word.  As you can see from the antibiotic resistant bacteria, evolution happens in many places at once. Instead of thinking about evolution as a line, we like to use the phrase rivers and tributaries.  And you can quite literally see what we mean by that as you watch the video.

‘Evolution is just a theory!’  

The word theory has a different definition in the scientific community. A theory is a scientific explanation that is supported by all existing evidence and continues to be supported by new research.  Decrying evolution as ‘just a theory’ is equivalent to saying you don’t believe in gravity because general relativity is ‘just a theory.’

‘I believe in adaptation but not evolution.’

They are literally the same thing.

 

Do you have any questions about evolution? Have you ever had to explain evolution to someone before?  Tell me about your experiences in the comments or on the contact page!

 

 

 

Bona fides and such

I received my BA in Anthropology from the beautiful SUNY Geneseo  in 2013, with a concentration in bioarchaeology.  I was lucky enough to work closely with the linguist Dr. Szafran as her TA, where I helped with the biological anthropology bits of her introductory anthropology module.

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I made my first trek into British academia at Corpus Christi, Cambridge in 2011, where I completed a survey of British Archaeology programme run through the Association for Cultural Exchange.

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spoil Lots of glamorous sifting was involved.

 

In 2012, I completed my bioarchaeology field school training in the gorgeous Menorca, Spain!

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After graduation in 2013, I changed my hair color and headed to the American Museum of Natural History for an internship with the North American Archaeology Laboratory.  And then stuck around like a parasite as an intern for the biological anthropology laboratory.

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Occasionally entertaining museum visitors

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And winning second place in halloween costume contests as Jane Goodall.

After that year of interning, I headed back to the Olde Country to start my MSc in Palaeopathology at Durham University.  My dissertation received Distinction (first honors) and examined the complex palaeoepidemiology of venereal syphilis and the colonial lens through which much of bioarchaeology has been undertaken.

After graduating in January 2016, I began my PhD thesis entitled Seeing is Believing: Excavation and Reclamation of Human Skeletal Remains in Post Conflict Guatemala.

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And now in December 2016, I’m about to take my preliminary viva.  If the university decides it still loves me, I’ll head to Guatemala!

If you have any questions about why I chose anthropology, how you can become an anthropologist, studying abroad in the UK, or interning in NYC, feel free to ask!

Forensic Anthropology – An Overview

The research I’m doing for my doctoral thesis falls under Forensic Anthropology, which means I specialise in the analysis of the human skeleton and I apply this in a legal context. The human skeleton can tell us a lot, but more often than not skeletal evidence leaves us with many unanswered questions.

Forensic anthropology is a science of last resort.  In an ideal forensic world, evidence is plentiful, victims are easily identifiable, and crimes investigated as soon as possible. Never do any of these things happen in forensic anthropology.  We are called in when the death occurred so long ago that the body has decomposed and traditional methods of identification no longer work. And because we’re a science of last resort, we operate with a certain level of uncertainty. We can measure things such as biological sex, age at death, past trauma, certain types of diseases, stature, but all of these within broad boundaries. We very rarely use skeletal remains to try and identify race anymore, as there just isn’t enough evidence that those methods actually work.

When we look at a pelvis to determine biological sex, for example, we rank on a spectrum how female or how male certain parts appear.  This spectrum is Very Male, Somewhat Male, Indeterminate, Somewhat Female, Very Female. Notice how we do not say “definitely female or definitely male.” So here is a human pelvis:

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We can look at the sub-pubic angle, shown at the base of each pelvis, for an indication of sex. When it’s narrow (left) we would label this Very Male, and when it’s wide (right) we would label it Very Female.

Looking at age can be even more vague! When we’re dealing with children we can be specific to within a couple of years, but past 25 it all goes downhill and we start giving age ranges in decades.  To further compound the work of the forensic anthropologist, most research that has been done to establish these methods of analysis has been done in population specific studies.  Now this can be great if you’re looking at a specific population that has been researched already, but in an increasingly globalised world much of this research is obsolete from a practical point of view.

Something more helpful in a forensic investigation would be using knowledge of past trauma or an illness which we can see in the skeleton. Like a broken arm or cancer. But this raises issues for anyone studying poor victims who have no medical or dental records to work from. And this is critical as it creates a socioeconomic disparity within the discipline. After the Indian Ocean Tsunami of 2004, victims with dental records were positively identified at a significantly higher rate, as dental analysis was the primary method of identification. But the majority of local victims did not have any dental records. One year later, 1252 European individuals were successfully identified with dental records compared to only 21 Thai victims. In these cases, we can ask surviving relatives for what’s called ante mortem evidence—that is evidence from before death including stories, testimonies, medical histories.

Usually at this point people ask about DNA evidence. It’s totally possible to do DNA analysis but it comes with its own set of problems. First, you need to have willing living participants to compare the DNA to and outreach to survivors can be limited, it’s expensive, and the DNA really doesn’t hold up too well over time. You need to have very specific samples from the skeleton and sometimes those just aren’t available because of the decomposition process, or because remains have been moved by perpetrators and are found incomplete. It also raises certain ethical questions. A forensic anthropologist at a conference over the summer gave a presentation about how DNA testing had revealed infidelity during investigations of mass graves in Iraq. Our first and foremost obligation is to the safety and wellbeing of our research participants, and as you can imagine this caused serious problems for them.

I work in mass grave contexts, specifically post genocide.  If that weren’t grim enough, there’s a whole other set of problems specific to mass graves.  In forensic anthropology, we usually look for something call Minimum Number of Individuals (MNI).  Notice how we don’t look for Actual or Estimated Number of Individuals. There are 206 bones in the adult human body, so we need to assume that if we find 206 bones in a grave that it’s one person not 206.  Sometimes the best we can do is put the pieces from the grave together until we get as many nearly complete skeletons as possible, and this means that we will inevitably miss individuals.   And in the case of genocide, often people are targeted for being from a specific genetic group or region, or because they look like they’re from that genetic group or region.  And those physical similarities can make identification of specific individuals that much more difficult.

For more information about the methodologies used by forensic anthropologists, keep your eye out for upcoming blog posts. But as always, feel free to ask any questions you may have in the mean time!

 

What is Anthropology?

It’s the most basic of questions, and the one I get most often.

Just what exactly is it that I do?  Here’s an overview of the basics of anthropology for some context.

ANTHROPO – from the Greek ánthrōpos meaning ‘human’

LOGY – denoting a subject of study

So anthropology literally means the study of humans.  Clearly this is a very broad concept and (as you might guess) anthropology is a broad discipline.  A common word used to describe anthropology is ‘holistic,’ which means that we research people from many angles including their cultures, languages, history, and biology.

Anthropology has gone through many shifts in how it has been practiced throughout its history, and anthropology is currently practiced slightly differently depending on the country.  In the United States, anthropology has four major subfields:

Cultural Anthropology – the study of cultures and societies

Linguistics – the study of language and its development  

Archaeology – the study of ancient material culture (artifacts, buildings etc)  

Biological Anthropology – the study of human biological development

All of these subfields also have subfields of their own and may interconnect to form new subfields.  For example, bioarchaeology is the study of human bones (biological anthropology) from archaeological sites (archaeology).  So instead of looking at what ancient communities created, we look at the people themselves to learn about their health, demography, migration and so on.  To make this even more complicated, this combined subfield then has its own subfields! Palaeopathology for example is the study of ancient diseases, trauma, and disability by looking at skeletal remains from archaeological sites, and is therefore a subfield of bioarchaeology.

In the United Kingdom, archaeology is in an independent department–although this separation is becoming less common even here.  Both the anthropology and the archaeology departments are housed in the same building in Durham, and will often work collaboratively.  For my MSc I studied palaeopathology in the Archaeology Department, now for my PhD I study biological anthropology in the Anthropology Department.

If any of you have watched TV lately, you will probably have heard of Forensic Anthropology.  This is a subfield of biological anthropology and my particular area of interest.  All this means is that we apply anthropological methods in a legal context.  We take those excavation techniques and our knowledge of the human skeleton, and we assist legal and investigative groups identify the long dead, establish cause of death, and prosecute perpetrators.

I’ll go into more detail about all of these fields and subfields in upcoming posts, but if you have any questions feel free to send me a message!