Victorian Human Skull from a private medical collection showing a trephine hole at the top of the head.

Provenance: from the private collection of a surgeon

Note: according to the vendor ( a retired Sugeon) the reason for the surgery may well have been that the patiant suffered a blow to the side of the head where the skull is thinnest just above the ears. Here there is an artery that can burst and cause bleeding in the brain ( known now as "talk and die" syndrome), the surgery would have been to releave the pressure in the brain.