# Throwing Light on the Past. A New Methodology for Analysing Activity-related Skeletal Changes in Humeri

Elle Liagre, Christopher J. Knüsel, Sébastien Villotte

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Elle Liagre, Christopher J. Knüsel, Sébastien Villotte. Throwing Light on the Past. A New Methodology for Analysing Activity-related Skeletal Changes in Humeri. 3rd Virtual Conference for Women Archaeologists and Paleontologists, Mar 2023, Online, France. . hal-04037374

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Submitted on 20 Mar 2023

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Distributed under a Creative Commons Attribution 4.0 International License
# Throwing Light on the Past

## A New Methodology for Analysing Activity-related Skeletal Changes in Humeri

Liagre Elleª, Knüsel Christopher J.ª, and Villotte Sébastienᵇ, c, d

The **medial epicondyle of the humerus** is a particularly relevant anatomical area to reveal **physical activities** performed during an individual's lifetime ¹⁻³ (e.g. throwing of objects, the use of axes and stone tool manufacture)⁴.⁵ and the **sexual division of labour** in past human groups. However, the qualitative recording of osseous alterations in this area remains particularly subjective and prevents large-scale comparisons.

The **main aim** of this research is to develop a novel method to record these alterations quantitatively through non-invasive 3D-imaging.

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### Collection

#### Collection of data

* **Prerequisite:** 3D model of humerus

* Can be obtained through CT-scanning, 3D surface scanning, or photogrammetry

### Preparation

#### Pre-processing of models

* Crop

* Orientate

* Filter (i.e. simplification, smoothing)

## Quantitative Analysis

### What? Topographical analyses

* quantify the whole-surface morphology,

* through complementary variables such as curvature, relief and complexity

### How? molaR package⁶ in an R environment

### Which analyses?

* **Dirichlet Normal Energy (DNE)**(curvature measure that quantifies the degree of surface bending)

* **Relief Index (RFI)** (relief measure calculated through the ratio of the 3D surface area to the 2D footprint)

* **Orientation Patch Count (OPC)** (complexity measure that counts the number of similarly oriented regions)

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## Conclusions & Prospects

* **Complementary shape variables** can be applied to quantify osseous alterations of the humeral medial epicondyle.

* Through **3D-imaging**, the method offers a **non-invasive** approach to more **objective** recording of these alterations.

* Application to **identified osteological collections** will improve understanding of the analyses' results and their interpretation.

* The method can **create new insights into physical activity and sexual division of labour in the past.**

### References

1. Dutour O, 1992. Activités physiques et squelette humain : le difficile passage de l'actuel au fossile. bmsap 4, 233-241. | 2. Dutour O, 2000. Chasse et activités physiques dans la Préhistoire : les marqueurs osseuxd'activités chez l'homme fossile. Anthropologie et Préhistoire 111, 156-165. | 3. Villotte S, Churchill SE, Dutour OJ, Henry-Gambier D, 2010. Subsistence activities and the sexual division of labor in the European Upper Paleolithic and Mesolithic: Evidence from upper limb enthesopathies. JHE 59, 35-43. | 4. Knüsel CJ, 1992. The throwing hypothesis and hominid origins. Hum. Evol. 7, 1-7. | 5. Villotte S, Knüsel, CJ, 2014. "I sing of arms and of a man...": medial epicondylosis and the sexual division of labour in prehistoric Europe. J. Archaeol. Sci. 43, 168-174. | 6. Pampush JD, Winchester JM, Morse PE, Vining AQ, Boyer DM, Kay RF, 2016. Introducing molaR: a New R Package for Quantitative Topographic Analysis of Teeth (and Other Topographic Surfaces). J Mammal Evol 23, 397-412.

<footnote>ª UMR5199 PACEA, University of Bordeaux, Bordeaux, France. | ᵇ UMR7206 Éco-Anthropologie, CNRS, MNHN, Université Paris Cité. Musée de l'Homme, Paris, France. |</footnote>

<footnote>ᶜ Quaternary environments & Humans, OD Earth and History of life, Royal Belgian Institute of Natural Sciences, Brussels, Belgium. | ᵈ Unité de Recherches Art, Archéologie Patrimoine, Université de Liège, Liège, Belgium.</footnote>