A cranium with annular modification

Cranial vault modification (CVM), the intentional reshaping of the head, indicated group affiliation for many prehistoric populations in the Andes.

Results from a sample of 423 individuals from 11 sites—spanning 150 km and almost 2500 years—showed specific attributes for each time period.

Among pre-Inca populations, the tabular type of modification appeared first and dominated the early Cuzco sample. The annular type appeared later during the Late Intermediate Period (AD 1000–1400). In the subsequent period of Inca imperialism, Inca individuals at central Cuzco sites were mostly unmodified. Meanwhile, modification rates soared outside the center of Cuzco.

Posterior view of a cranium with multiple healed trepanations

In this study, patterns of prehistoric trepanation in the southern highlands of Peru were examined through an analysis of 11 Cuzco-region burial sites. Trepanations were found in 66 individuals, with several individuals exhibiting more than one trepanation, for a total of 109 perforations observed.

Survival rates showed a significant increase over time, apparently reflecting improvements in trepanation technique through experimentation and practical experience.

In many cases, trepanation appears to have been used as a medical treatment in response to cranial trauma.

Healed cranial fracture on the frontal bone of an Inca individual

Here, the role of warfare in the rise and expansion of the Inca Empire was examined through cranial and post-cranial trauma patterns in a sample of 430 Cuzco skeletons.

The results suggested that violent conflict did rise during the period of Inca state development. Subsequently, in the Inca Imperial Period, violent conflict apparently predominated in the regions outside the capital city. However, the overall frequency of violent injuries was low and there were few indications of massive trauma.

These findings suggested that while warfare was part of Inca imperial expansion, it may have been exaggerated by the Spanish chroniclers.

The strontium ratio from dental enamel helped to explain this individual's geographic origins

This study used strontium isotope analysis to examine patterns of prehistoric migration in the Cuzco Valley. Human dental enamel samples from the Cuzco Valley site of Chokepukio were analyzed and compared to the local 87Sr/86Sr signature established through faunal specimens.

The results showed substantial evidence for migration during the time of Inca imperialism (AD 1400 - 1532). Among these migrants, variation in 87Sr/86Sr values suggested that individuals emigrated from geologically diverse locations.

These data, along with ethnohistoric evidence, revealed how Inca labor policies reconfigured the composition of populations in the Inca heartland.