A possible case of prophylactic supra-inion trepanation in a child cranium with an auditory deformity (pre-Columbian Ancon site, Peru)

Abstract

We had the opportunity to examine a pre-Columbian Peruvian child (about 4–5 years old) cranium with a healed lesion above the inion on the occiput. It has previously been claimed that supra-inion lesions represent traces of prehistoric trepanation for ritual or prophylactic reasons in childhood, a practice termed ‘trepanation supra-iniana’. An alternative hypothesis claimed that such lesions mainly result from abnormal long-term compression caused by artificial deformation. We describe several macroscopic characteristics of the cranium and discuss the claim that it is a case of ‘trepanation supra-iniana’. The cranium is also characterized by an artificial anterior–posterior deformation, unilateral stenosis of the external auditory canal on the right side, and small drill holes on this same side in the frontal region. The supra-inion lesion, consisting of a shallow depression and a fissure-like orifice, is located slightly to the right on the occiput. The morphological-pathological state of the lesion is analogous to the healing of a trepanation by scraping. These observations suggest that the lesion did not result from artificial compression by head deformation, but from the infliction of trepanation identical to ‘trepanation supra-iniana’. The observed stenosis of the external auditory canal is clearly congenital. It is considered that this clearly visible auditory deformity was the primary reason for conducting the ritual or prophylactic trepanation. The small drill holes in the frontal region may have been a post-mortem or peri-mortem trepanation of a ritual or superstitious nature.