Archaeology of Disease

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Quick Tips – Common Questions: Why are some diseases more easily identified on skeletal remains than others?

This is a Quick Tips post providing a basic answer to a commonly asked question often faced within the field of archaeology and anthropology.

Some diseases are more easily to identify on skeletal remains due to leaving tell-tale signs in the bones preservation. An easy example of this is osteoporosis; this condition leaves the inners of bones a lot more porous which is easier to visually assess and compare to a ‘healthy’ individual’s skeletal remains.

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Some diseases are more easily to identify on skeletal remains due to leaving tell-tale signs in the bones preservation. An  example of this is osteoporosis; this condition leaves the inners of bones a lot more porous than normal bones.

A study by Hershkovitz & Rothschild (1997) highlighted how certain medical conditions, in their study sickle cell anaemia, affects the bone growth and development. Hershkovitz & Rothschild found that due to the iron deficiency from sickle cell anaemia caused porotic hyperostosis (symmetrical osteoporosis) on the parietal bone as well as others. They were able to visually diagnose this due to the characteristic ‘pores’ over the skull.

Another example of an easily identifiable disease is tuberculosis (TB), TB can cause devastating bone damage. A recent archaeological study by Lewis (2011) looked into a population who suffered from TB. Lewis visually analysed the skeletal remains of a juvenile population from Poundbury Camp, Dorset. The TB infection caused numerous ailments to the infected, such as fever, but it’s the skeletal damage which gave the indication that the person suffered.  Amongst the population there was a high instance of skeletons with necrosis and lytic lesions characterised by minimal bone formation.  Many of the juvenile’s vertebrae displayed new bone formations which could indicate the presence of a paravertebral abscess. Many of the metatarsals were also displaying evidence of new bone formation which they concluded could be indicative of tuberculous dactylitis. Osteomyelitis, infection of the bone, was also found on a few mandibles and visually diagnosed due to its characteristic small pores found in a localised area. It is this characterised skeletal damage, seen on numerous cases during known TB outbreaks, which cause more diseases to be easily identified by eye due to the skeletal anomalies.

There are problems when trying to differentiate certain diseases for example; TB with brucellosis (undulant fever). As they both produce spinal lesions it is necessary to observe the other characteristic skeletal damage (new bone formation and osteomyelitis) to correctly identify it as a TB infection. Another slight difference between TB and brucellosis is that the spinal lesions are more sclerotic and regular than those from a TB infection (Lewis, 2011).

These porous bones and unexpected bone formations are easily observed, as they are not what’s expected during the known skeletal development found in healthy persons. Problems arise with diseases that do no damage to the skeleton, but instead affect soft tissue and muscles. These illnesses are harder to identify as they decay over time leaving only trace elements in the surrounding soils which would then hold the key for disease identification.

References:

Hershkovitz, I. Rothschild, B. et al. 1997. Recognition of sickle cell anemia in skeletal remains of children. American Journal of Physical Anthropology. Volume 104, Issue 2. 213-226.

Lewis, M. 2011. Tuberculosis in the non-adults from Romano-British Poundbury Camp, Dorset, England. International Journal of Paleopathology. Volume 1, Issue 1. 12-23.

To learn how archaeologists and anthropologists use teeth to age skeletal remains, read our Quick Tips: How To Estimate The Chronological Age of a Human Skeleton – Using Dentition to Age Subadults. Or to read more of our interesting Quick Tips, click here.

Quick Tips: Identifying Dental Diseases – Dental Caries.  
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Quick Tips: Identifying Dental Diseases – Dental Caries.  

In our previous Quick Tip post on identifying dental diseases, we gave a basic overview on the disease dental/enamel hypoplasia. If you haven’t read it, you can find it by clicking here.

Dental caries, also known as tooth decay, is thought to be the most common of dental diseases. This is due to it being recorded within archaeological populations more frequently than other dental diseases. It is an infectious and spreadable disease, which is the result of the fermentation of carbohydrates by bacteria that are present within teeth plaque. Its appearance can sometimes be observed as small opaque spots on the crowns of teeth, to large gaping cavities.

dental caries

Dental caries appearance can sometimes be observed as small opaque spots on the crowns of teeth, to large gaping cavities.

Dental caries occurs when sugars from the diet, particularly sucrose, are fermented by the bacteria Lactobacilus acidophilus and Streptococcys mutans, which are found within the built up plaque. This fermentation process causes acids to be produced, which in turn break down and demineralises teeth leaving behind cavities.

Powell (1985) divided the causes of dental caries into different areas, which are;

  • Environmental factors, the trace elements in food and water (i.e fluoride in water sources may protect against caries).
  • Pathogenic factors, the bacterial causing the disease.
  • Exogenous factors, from diet and oral hygiene.
  • Endogenous factors, the shape and structure of teeth.

Any part of the tooth structure that allows the accumulation of plaque and food debris can be susceptible to caries. This means that the crowns of the tooth (especially with molars and premolars due to the fissures), and the roots of the teeth are the areas most commonly affected by dental caries.

References:

Lukacs, J.R. 1989. Dental paleopathology: methods for reconstructing dietary patterns. In M.Y. Iscan and K.A.R. Kennedy (eds), Reconstruction of life from the skeleton. New York, Alan Liss, pp. 261-86.

Powell, M.L. 1985. The analysis of dental wear and caries for dietary reconstruction. In R.I. Gilbert and J.H. Mielke (eds), Analysis of prehistoric diets. London, Academic Press, pp. 307-38.

Ubelaker, D.H. 1989. Human Skeletal Remains: Excavation, Analysis, Interpretation (2nd Ed.). Washington, DC: Taraxacum.

White, T.D., Folkens, P.A. 2005. The Human Bone Manual. San Diego, CA: Academic Press. Pg 392-398.

This is the second post of the Quick Tips series on identifying dental diseases. The next post in this series will focus on how to identify calculus (calcified plague), and highlight the cause of this dental disease. To read more Quick Tips in the meantime, click here.

If you’re new to the realm of archaeological, anthropological and forensic sciences (AAFS), or are a student needing sturdy and reliable references, or wondering “what archaeology or anthropology textbooks are good?” Check out our new ‘Useful Literature’ page for suggestions from peers and professors!

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Quick Tips: Identifying Dental Diseases – Dental/Enamel Hypoplasia.

In our previous Quick Tip post on identifying dental diseases, we gave a basic overview on the different diseases that are observed. If you haven’t read it, you can find it by clicking here.

Dental hypoplasia is a condition that affects the enamel of a tooth. It is characterised by pits, grooves and transverse lines which are visible on the surface of tooth crowns. The lines, grooves and pits that are observed are defects in the enamels development. These defects occur when the enamel formation, also known as amelogenesis, is disturbed by a temporary stress to the organism which upsets the ameloblastic activity. Factors which can cause such stress and therefore disrupt the amelogenesis include; fever, malnutrition, and hypocalcemia.

Figure 1: An example of linear enamel hypoplasia.

Figure 1: An example of linear enamel hypoplasia.

It has been noted that enamel hypoplasia is more regularly seen on anterior teeth than on molars or premolars, and that the middle and cervical portions of enamel crowns tend to show more defects than the incisal third. This is due to the amelogenesis beginning at the occlusal apex of each tooth crown and proceeding rootward, towards where the crown then meets the root at the cervicoenamel line.

Figure 2: Anatomy of a tooth. Note the top third is known as either the occlusal third if in molars, or the incisal third when the tooth is an incisor or canine.

Figure 2: Anatomy of a tooth. Note the top third is known as either the occlusal third if in molars, or the incisal third when the tooth is an incisor or canine.

By studying these incidents of enamel hypoplasia within a population sample, we can be provided with valuable information regarding patterns of dietary stress and disease that may have occurred within the community.

References:

Lukacs, J.R. 1989. Dental paleopathology: methods for reconstructing dietary patterns. In M.Y. Iscan and K.A.R. Kennedy (eds), Reconstruction of life from the skeleton. New York, Alan Liss, pp. 261-86.

Ubelaker, D.H. 1989. Human Skeletal Remains: Excavation, Analysis, Interpretation (2nd Ed.). Washington, DC: Taraxacum.

White, T.D., Folkens, P.A. 2005. The Human Bone Manual. San Diego, CA: Academic Press. Pg 392-398.

This is the second post of the Quick Tips series on identifying dental diseases. The next post in this series will focus on how to identify dental caries and highlight the cause of this dental disease.

To read more Quick Tips in the meantime click here, or to learn about basic fracture types and their characteristics/origins click here!

Quick Tips: Identifying Dental Diseases – The Basics.
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Quick Tips: Identifying Dental Diseases – The Basics.

In a previous Quick Tip post we briefly touched on teeth in anthropology/archaeology by providing a basic answer to the question, “What can an anthropologist tell from the examination of teeth?”, which can be found by clicking here.

“No structures of the human body are more likely to disintegrate during life than teeth, yet after death none have greater tenacity against decay” – Wells, 1964.

Teeth are the hardest and most chemically stable tissues in the body; because of this, they’re sometimes the only part of a skeletal remain to withstand the excavation. Even though teeth are the most robust structures of a skeleton, there are numerous diseases that can affect them. This is due to teeth interacting directly with the environment and therefore are vulnerable to damage from physical and biological influences. It is from these diseases, that archaeologists and anthropologists can learn a wealth of information on an individual or population’s diet, oral hygiene, dental care and occupation.

Lukacs, 1989, classified dental diseases into four categories, which are;

  • Infectious – This is one of the more common disease types found within archaeological populations. An example of an infectious dental disease is caries.
  • Degenerative – This is where the dental disease occurs over time as the person ages. An example of degenerative dental disease includes recession of the jaw bone.
  • Developmental –These dental diseases develop due to environmental and lifestyle factors, such as malnutrition. An example of this type of disease is enamel hypoplasia.
  • Genetic – These types of diseases are caused by genetic anomalies.

The main dental diseases that are observed within an archaeological or anthropological context are;

If the dental disease listed above is a link, it means that I have already covered it in an individual blog post and can be found by following the link.

Each of these dental diseases has their own characteristics which allows them to be easily distinguished from one and another. In the next few posts of this Quick Tips series, we will be focusing on each dental disease individually, and highlighting their aetiology and physical characteristics.

References:

Buikstra, J.E., Ubelaker, D.H. 1994. Standards for Data Collection From Human Skeletal Remains. Fayetteville, Arkansas: Arkansas Archaeological Survey Report Number 44.

Lukacs, J.R. 1989. Dental paleopathology: methods for reconstructing dietary patterns. In M.Y. Iscan and K.A.R. Kennedy (eds), Reconstruction of life from the skeleton. New York, Alan Liss. Pg 261-86.

Ubelaker, D.H. 1989. Human Skeletal Remains: Excavation, Analysis, Interpretation (2nd Ed.). Washington, DC: Taraxacum.

Wells, C. 1964. Bones, bodies and disease. London, Thames and Hudson.

White, T.D., Folkens, P.A. 2005. The Human Bone Manual. San Diego, CA: Academic Press. Pg 392-398.

This is the first post of the Quick Tips series on identifying dental diseases. The next post in this series will focus on how to identify dental/enamel hypoplasia and highlight the cause of this dental disease.

To read more Quick Tips in the meantime, click here, or to learn about basic fracture types and their characteristics/origins click here!

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Quick Tips: Fracture Types – The Basics Pt 2.

In my previous Quick Tips, which you can find by clicking here, you were introduced to the first six basic types of fractures, what the main causes of fractures are, and the two main categories they are classed in. It is important that you know the information in the previous Quick Tips post before learning these last few basic fractures, as it discussed the fundamentals of fractures.

Basic Fracture Types:

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Fracture Types: A) Butterfly, B) Longitudinal, C) Segmented, D) Hairline, and E) Avulsion.

A) Butterfly Fracture: Butterfly fractures usually affect long bones and can be caused by car accidents or by being knocked side on.

B) Longitudinal Fracture: As a transverse fracture is a bone along the horizontal axis, a longitudinal fracture is along the vertical axis.

C) Segmented Fracture: This is when the bone has fractures in two parts of the same bone causing the bone to break into larger bone fragments which are separated from the main body of a fractured bone.

D) Hairline Fracture: These fractures are also known as ‘stress fractures’. These types of fractures are very difficult to diagnose and once they heal there may be no evidence left to see. These are very difficult, if not impossible to identify when in an archaeological context.

E) Avulsion Fracture: Avulsion fractures are characterised as the separation of a small fragment of bone at the site of attachment of a ligament or tendon.

The next Quick Tips post will discuss the ‘named fractures’ that can be discovered in archaeological contexts, such as the familiar Bennett’s and Parry’s fracture, and their origins and common causes.

This post was put together by using knowledge from my degree and supplemented with the textbook ‘The Archaeology of Disease’ by Charlotte Roberts & Keith Manchester. If you’re interested in the latest scientific and archaeological techniques used to understand the diseases of past populations, you should check it out!

This is the second post of a set on fractures, so keep your eyes open for the other posts. To view other Quick Tips posts click here!

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Quick Tips: Fracture Types – The Basics.

In my previous Quick Tips post I addressed how to distinguish between ante, peri and post-mortem fractures, click here if you haven’t read it yet. 

In this Quick Tips post I will show you some ways to identify and deduce common fracture types and their key characteristics. The definition of a fracture is a break in the continuity of a bone. There are three major causes of fractures: acute injury (an accident); underlying disease which then weakens the bone making it susceptible to fractures; and repeated stress (as seen in athletes).

All fracture types can be placed in two categories; open and closed. An open fracture, also known as a compound fracture, is where the bone breaks through the skin causing an open wound. It is called an open fracture as there is an open connection between the fracture site and skin. A closed fracture is where the bone has no connection between the outer skin surface and the fractured bone itself; it does not cause an open wound. A closed fracture is classed as a ‘simple fracture’.

Basic Fracture Types:

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Fracture Types: A) Transverse, B) Oblique, C) Spiral, D) Comminuted, E) Greenstick, and F) Impacted fracture.

A) Transverse Fracture: This is when the break of a fracture is in a horizontal line, it is the simplest fracture type.

B) Oblique Fracture: This fracture is a break which extends in a slanting direction.  Oblique fractures are caused by indirect or rotational force.

C) Spiral Fracture: As you can guess from the name, this is a fracture which is characterised by a spiral. It is often denoted as being caused by torsion or force onto the bone.

D) Comminuted Fracture: A comminuted fracture is characterised from the splintering of the bone. This causes the fracture to be made up of two or more pieces. This fracture is common in road-traffic accidents and these fractures are less likely to heal in a functionally satisfactory manner.

E) Greenstick Fracture: This occurs when a transverse fracture is incomplete. This fracture is seen mainly in children due to their young, immature bones which rarely break the whole width.

F) Impacted Fracture: This occurs when the bone is broken and not displaced but the two fractured ends are forced together. This produces a rather stable fracture which can heal readily but there may be some length lost.

This post was put together by using knowledge from my degree and supplemented with the textbook ‘The Archaeology of Disease’ by Charlotte Roberts & Keith Manchester. If you’re interested in the latest scientific and archaeological techniques used to understand the diseases of past populations, you should check it out!

This is the first post of a set, click here to read the second post. To view other Quick Tips posts click here!