Research into the reasons for trepanation (2016)

For a large part of human prehistory, people around the world practised trepanation: a crude surgical procedure that involves forming a hole in the skull of a living person by either drilling, cutting or scraping away layers of bone with a sharp implement. Many trepanned skulls show signs of cranial injuries or neurological diseases, often in the same region of the skull where the trepanation hole was made. Now Gresky, Batieva and other archaeologists have teamed up to describe all 12 of the obelion trepanations from Southern Russia.

Source: www.bbc.com