Researchers tracking down centuries-old bones from dissected individuals were able to show how tools and autopsy techniques have changed over time. And it looks like we’ve come a long way. The work was presented at the annual AAAS meeting in San Jose, California, last week. 

To better understand our history with anatomical studies, Jenna Dittmar and Piers Mitchell from the University of Cambridge examined multiple skeletal remains from individuals who were dissected and autopsied between the 1600s and the 1900s. These were collected from a range of archaeological sites throughout the U.K., including recently excavated burial grounds at hospitals, prisons, and workhouses (public institutions where people can board in exchange for work). Based on these remains, they were able to figure out how these procedures were conducted, what instruments were used, and how the bodies were disposed. 

Oftentimes, their archaeological excavations would turn up dismembered limbs and disembodied skulls—which suggests that a single cadaver was split between many medical students, Science reports, especially since there weren’t very many (legal) bodies available for science. “There were so many students, they couldn’t all be given a single cadaver,” Dittmar says, according to the Guardian. “So they were given them in pieces. They might have a knee one day, an elbow another. As long as they dissected two complete bodies they could be medically licensed. It didn’t matter if it was in bits.”

Using scanning electron microscopy to examine the cut marks left behind on the bones, the team reconstructed the kinds of surgical tools that were used and how they changed over time. As Science explains: The crude instruments resembling “woodworking tools” in the 1700s gradually became thinner and thinner, and the cuts more refined as techniques improved. Early dissectors, for example, sometimes sawed off the top of the skull horizontally, but by the late 1880s, arcs were cut across the back of the skull to keep the brain intact for studying. 

The team also uncovered a late-1800s skull that had been sliced vertically (like something out of the laser room in Resident Evil). Click here to see a photo of this rare specimen from the University of Cambridge’s collection. According to New Scientist, it was probably used as a teaching aide. “These individuals have sometimes been taken from graves and dissected, but they have also contributed massively to modern medicine and modern surgery,” Dittmar explains, “whether they were willing participants or not.”