Osteology 101- Part 1/5: What is Osteology?

https://www.youtube.com/watch?v=vlQHFVE_3FU

Human osteology is a branch of anatomy that focuses on the study of the human skeleton (see osteo “bone”, and logy “the study of”). Osteoarchaeology, specifically, is the study of human remains from archaeological sites. The field of osteology is rather important, especially in archaeological contexts, as it allows a researcher to infer additional contextual information from the actual individuals who inhabited the site under excavation. The role of the osteologist is to identify human bones from those of non-human material (i.e. animal bones), and to determine as much additional information about the bones they are confronted with. The skeleton is divided into the axial skeleton: the vertebral column, the rib cage, and the skull; and the appendicular skeleton: the pectoral girdles, the pelvic girdle, and the upper and lower limbs.

The Human Skeleton

Not only do the presence of human remains on a site spark curiosity, but a single skeleton can provide an abundance of data on the individual’s life from their age, sex, and stature all the way to past struggles such as diseases, accidents, and developmental instabilities. The anatomy of the skeleton slightly differs between each of us depending on our genes. However, the skeleton reflects the environment as well. The teeth, for example, are the only bone in the human body that directly interact with the environment (e.g. through eating, clenching items in the teeth, and even as simple as brushing the teeth!). The remaining biological body external from the skeleton can clearly change depending on your diet, accidents, and diseases. Where osteology comes into play, is what can be inferred following death. Naturally, the body as an organism changes throughout time as a whole. However, at an eventual point following death, the softer tissues of the body such as the muscles, ligaments, organs, veins, tendons, nerves, and arteries will decompose. What is typically left behind? The skeleton. A bony map of the individual’s life.

So, what can we infer when faced with a human skeleton? The most basic of inferences are estimations on the individual’s age, sex, and stature. As a person ages, their skeletal morphology will grow and change. This can be understood quite simply with the human body being composed of up to 300 bones at birth and decreasing to about 206 bones by adulthood. What happened in that time is that the bones grew and fused together, to create a strong and resilient foundation to the rest of the biological body. Observing these fusions in the epiphyses and the skull are one way to determine an age estimate, however, changes also occur in places such as the pelvis and the teeth, that can be observed and calibrated to estimate an osteological age. Estimating sex, on the other hand, is slightly more fluid. There can be subtle differences between sexes in the morphology of some parts of the skeleton. Sex estimation is traditionally done on a 5-point scale: Female, Probable Female, Indeterminate, Probable Male, Male. Though there are differences in male and female pelvises, predominantly due to the female pelvis function in facilitating child birth, many individuals carry characteristics of both traditional “male” and “female” anatomical forms in the pelvis and the skull. Determining a sex estimate is done by observing numerous characteristics and classifying them into one of the five aforementioned categories. After collecting this information, the results are averaged to determine an estimation on the individual’s sex. The stature, or individual’s height, is inferred via measurements of the long bones, namely the humerus, femur, and tibia. When these bones are unavailable, the ulna, radius, and fibula can also provide a range. There are several methodologies that are used within osteology to determine these estimates. For additional information, please refer to the suggested reading below.

Bone Growth

Bone Growth

Images (left to right): General bone growth, epiphyseal growth (young person long bone vs adult long bone), and estimating age using the pubic symphysis (ageing a skeleton example).

Apart from the general information one can collect from a single skeleton, pathological conditions can be observed as well. This branch of science within osteoarchaeology is called palaeopathology and concerns itself with ancient diseases that may have been reflected in the skeletal body. In addition, accidents or traumas resulting in breakage of bone, or officially bone fractures, can also be observed. Much of the time when the bone had already healed while the individual was still alive! However, this will be discussed in future episodes.

Having knowledge in the field of osteology can be applicable to work within archaeology, paleontology, osteology, forensic research, medical science, and law enforcement – to name but a few. The field is incredibly important, especially in the context of archaeological civilizations. This is considering that there are human remains present on site, what better way to infer more on an ancient site, than through the bones of the people who inhabited it!

Thanks again to Jude to writing this piece and being the awesome lady that she is! Also huge thank you to Leiden University for letting us film at the Laboratory for Human Osteoarchaeology. For more information, click here to visit their website.

Have any questions?

Email me at: digitwithraven@gmail.com