At least that’s the more traditional view of why people cut holes in their skulls. The idea that the procedure was supposed to release the demons that ancient people thought caused migraines is actually likely inaccurate. It probably comes from a 20th-century English lecturer, Sir Thomas Lauder Brunton, who first suggested the idea during a presentation on migraines. It was at the time- and remains-pure speculation. It’s one of the many myths surrounding the practice. And while it remains a possibility that our ancestors thought they were releasing demons, there are probably better explanations.
Trepanning, or the cutting of holes in the skull, sounds crazy to us today. But it clearly didn’t to our ancestors. The bones of people with obvious holes cut into their skulls have been found everywhere from France to Siberia to the Americas. In fact, it may be one of the oldest surgical procedures in human history, with examples of trepanned skulls dating back to more than 8000 years ago. This dating would put these earliest trepanations in the Mesolithic, or Middle Stone Age, meaning that the procedures were likely performed with chipped stone tools.
But even with these crude surgical devices, there’s evidence that many of the people who had their skulls cut actually survived. Trepanned skulls have been found with evidence of bone growth, which suggests that the patient lived for years afterward. This isn’t as surprising as it sounds. If no cuts were made into the dura, or the membrane that separates the brain from the skull, there was actually little risk from the surgery itself besides infection. And if dura remained intact, the cut into the skull is small enough, and was eventually covered with regrown skin, then the soft tissue of the brain would still be relatively protected.
In truth, we don’t know for certain why people wanted to be trepanned. The majority of the procedures might have served a more ritualistic purpose. Many groups of people throughout history have changed the shapes of their bodies for religious reasons, or just to set themselves apart from other people. The Huns, for instance, used to bind the heads of their children so that their skulls would grow into elongated shapes. It’s possible that some cases of trepanning were done for similar reasons. If so, then we have no record of what exactly it was supposed to achieve.
There’s also the possibility that these ancient examples of trepanning actually were supposed to cure illnesses, though we don’t know which ones. Given the age of the bones in question, it’s hard to tell exactly what sort of medical conditions the people who went through the procedure might have been suffering from. And many conditions that our ancestors might have been trying to cure- if that’s what they were trying to do- by cutting holes in the skull, like headaches, epilepsy, or mental illness don’t leave any obvious signs behind. But we do know that at some points in history, trepanning was absolutely an accepted medical procedure. In some cases, it was actually the best option an ancient surgeon had.