Trephination, or making a hole in the skull of a living person, seems to have been the first surgical practice. But why would people cut holes in the skull? There are many theories about the practice, which first appeared during the Neolithic period. It was most often performed on adult males - although examples have been found in the skulls of children and women. One theory is that it might have been used for the exit or entrance of spirits believed to cause illness, or as a cure of convulsions, headaches, infections and fractures. It has also been suggested that the reason for trephination was the collection of skull discs, called rondelles, for charms or amulets.
The practice continued in Ancient Egypt, where scrapings from the skull were used to make potions. Both Hippocrates and Galen wrote about trephining and the practice continued throughout the Middle Ages and into the Renaissance. These operations were often highly successful and many people must have survived the treatment, as is evidenced by skulls that show bone regrowth.
Trephination is still used in medical practice today, although it is reserved for the relief of epidural and subdural haematoma.