The Sciences

The Curious Case of the Cow With a Hole in Its Skull

The hole offers a window into a gruesome yet intriguing 'medical' procedure thousands of years old.

In April this year, scientists reported the results of their analysis of a cow’s skull, believed to be around 3,500 years old and which had been found on France’s Atlantic coast. The scientists found some surprisingly smooth, circular holes in the skull – too clean to have been caused by a blow from a blunt object or goring by another animal’s horn. No; the holes bore the signature signs of careful drilling.

The hole’s shape and the way the bone had healed around the aperture led the scientists to claim that this was probably the earliest evidence of veterinary surgery.

If drilling holes in the skull sounds more like medieval torture than medicine, you’d be surprised. Drilling holes in the skull – called trepanation – is a medical procedure that has been practiced for many millennia. It is the oldest surgical intervention known to humankind. It was practiced by Hippocrates and Galen.

In the Stone Age, the technique involved scraping the skull with tools made of obsidian or flint. During the Renaissance, these materials evolved to a piece of glass or blades of metal. Later, they were replaced by a circular saw and then, in modern times, an electric drill.

Surgeons routinely perform trepanations to expose the brain before surgeries, particularly in the case of head injuries, when the inflamed brain pushes up against the skull. Removing a part of the skull relieves the pressure and helps reduce brain damage.

Trepanated skulls have been found in almost all eras around the world, peaking in the late Neolithic era (4,000-5,000 years ago) in Algeria, Canada, France, Italy, Mexico, Mongolia, Peru, Ukraine and the US. The oldest such skull was found in North Africa, dated about 10,000 years old.

The skull from Peru

Credit: NeONBRAND/Unsplash

Credit: NeONBRAND/Unsplash

Why did ancient humans drill holes in the skull? Was it superstition or medical practice? These questions have not been answered to this day.

At the same time, trepanated animal skulls are very rare. The cow skull found in France is believed to be the first confirmed case of a trepanated animal skull. And why humans drilled into that particular skull is mystery.

Theories explaining trepanation range from religious practice, group-initiation ritual to medical treatment of epilepsy, head injury and ‘madness’. Drilling holes in the skull is consistent with medical beliefs of that time – that releasing bad spirits, removing “stones” or draining bad blood could treat various illnesses. Ancient humans also believed in the supernatural power of skulls: powdered skulls were applied on people’s heads, and hung amulets made of skull fragments around their necks.

The first trepanated human skull that attracted the Western medical world’s attention was found in 1865. Then, Ephram George Squier, an American diplomat, had purchased a skull from a Peruvian collector. Squier had a passionate interest in archaeology and Central American culture. The skull he had bought had a rectangular hole about 1.5 cm long and 1.7 cm wide, with distinct marks around it. These marks had puzzled him.

He brought it back to the US and showed it to leading surgeons in New York, who confirmed that the marks had been made by wilful drilling. To dig deeper, Squier contacted Paul Broca, the most famous medical scientist of the time. Broca was a pioneer of modern neuroscience and anthropology – and also performed trepanation surgeries.

Broca took great interest in the Peruvian skull and began to study many other such skulls. He concluded that it would have required skilled craftsmanship to drill a hole like the one in the skull Squier had brought to him. He surmised that the person to whom the skull belonged might have survived for a week – at best – after the surgery. He also concluded that the skull was pre-Columbian, meaning the surgery had been performed by Native Americans.

The first confirmed trepanation in India was in a 4,300-year-old skull found in a site called Burzahom in Kashmir. Anek Sankhyan, a palaeo-anthropologist, discovered it in 2001. Some other skulls that were believed to have been trepanated were also found: one each in the Harappan sites of Lothal and Kalibangan and one in Maski, Karnataka. However, no trepanated animal skulls have been found in India thus far.

In Kenya, the Kissii tribe continues to perform trepanation as a cure for mild headaches following head injuries, and the practice has been well documented.

A dangerous craze

Credit: Linda Xu/Unsplash

Credit: Linda Xu/Unsplash

Looking at the French cow skull through an electron microscope, scientists noticed patterned markings around the holes that were similar to other trepanated human skulls found in the same region. Fernando Ramirez Rozzi, a palaeobiologist at the French National Centre for Scientific Research and one of the study’s authors, favours the idea that the person who trepanated the cow skull could have been practising their surgical skills.

“The cow is very abundant in that site, people live on livestock; what would be the interest to heal a cow which represent the most abundant animal among the archaeological remains?” Rozzi told The Wire. This is backed by trepanated human skulls found in that area showing signs of great skill. This could be because the person who performed these drills might have practiced on animals first.

Apart from surgeons and anthropologists, trepanation caught the people’s fancy as well. ‘Cure of Folly’, the work of Hieronymus Bosch, a Dutch painter of the 15th century, depicts a scene where a man is seated in a chair while another is drilling a hole in his head. A bit of text reads, “Master, dig out the stones of folly, my name is Castrated Dachshund.” Here, Bosch is making fun of the procedure.

In another painting, created by Peter Bruegel in 1559, a woman is seen performing a trepanation and showing a crowd of onlookers a stone she has seemingly extracted from the skull. Her assistant is seen crouched under a table with a basket of stones, suggesting a hoax.

Other paintings from the time depict trepanation as a serious medical procedure used to cure mental illnesses.

For all the gore, modernity has flirted with the procedure every now and then. In the 1960s, during the counter-culture movement, some people associated trepanation with expanding one’s consciousness and experiences beyond those afforded by one’s normal sensory faculties. This idea was popularised by the The book ‘Bore Hole’, by Joe Mellen, popularised this idea and describes a self-trepanation episode in gruesome detail.

Peter Halvorson, an American who got himself trepanated, runs the International Trepanation Advocacy Group, plus a website, pushing the procedure as a cure for depression and to boost one’s general ‘vigour’. In 2000, he was arrested for practicing medicine without a licence when he was caught drilling holes in a willing patient’s skull. However, the idea itself became so well-received that, in 2000, the British Medical Journal issued a public warning against trepanation.

What could have motivated humans of the Neolithic period to drill holes in the skulls of fellow humans, and in livestock? We don’t know. The healing patterns, the lines of incision and the shape of holes all prompt awe; you marvel at the surgeon’s skills, which couldn’t have come to be without thoughtful practice.

This is a testament to the knowledge of ancient humans, their level of awareness – that the skull or maybe even the brain could be the cause of illnesses – and their attempts to alter their destiny by drilling holes in their heads.

Leslee Lazar is a cognitive neuroscientist and a visual artist. He currently teaches at IIT Gandhinagar and tweets @leslee_lazar.

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