Archaeological origins of cranial surgery: trephination in Mexico.

Archaeological excavations in Mexico and South America have provided evidence that trephination of the skull was performed by the pre-Hispanic Mexican and Incan cultures. Because those who performed such operations on the skull, presumably for ritual, prophylactic, or therapeutic reasons, can be considered predecessors of modern intracranial surgeons, their techniques and results are a subject of considerable current interest. This article, adapted from a lecture presented to the 1986 Congress of Neurological Surgeons, summarizes published descriptions of 34 trephined South and Central American and Mexican skull specimens, 16 of which were unearthed in Mexico and are currently available for review in anthropological museums in Mexico. Examples of several surgical techniques used on these skulls are presented. Although some trephinations were performed by these early cranial surgeons for apparently therapeutic reasons on skulls with obvious evidence of traumatic fractures, the interpretation of the medical, psychiatric, cultural, or religious significance of such procedures remains largely speculative.