The above tools, called trephines or trepans, were used to cut a circular hole in the skull. Practiced for tens of thousands of years, trepanation is believed to be the oldest surgical procedure practiced by humans (Frey, 2005). Early trepanations are thought to have been treatment for psychological disorders, epilepsy, and headaches (Frey, 2005).
The all-metal trephine pictured above is from after 1860, while the one with the ebony handle is from between 1860 and 1870. Both have Galt-style blades, characterized by the angled grooves on the cutting crown. This style was meant to produce less bone dust than the older straight crown. During the 19th century, trephines were used to relieve pressure on the brain following cranial injuries (Bakay, 1985).
Bakay, L. (1985). The early history of craniotomy: From antiquity to the Napoleonic Era. Springfield, IL: Charles C. Thomas.
Frey, R. J. (2005). Trepanation. The Gale Encyclopedia of Alternative Medicine. Detroit: Gale.
(UT Health Science Center Historical and Special Collections has initiated a project to identify items in a collection of medical artifacts. If you have further information about the items highlighted, please comment.)