That is known as the perforator drill bit - https://www.reddit.com/r/toolgifs/comments/z2zikm/cranial_perforator_to_drill_through_skull_without/ https://www.red

That is known as the perforator drill bit - https://www.reddit.com/r/toolgifs/comments/z2zikm/cranial_perforator_to_drill_through_skull_without/ https://www.reddit.com/r/toolgifs/comments/z2zikm/cranial_pe... Used to make burr holes so that the dura can be stripped away from the skull using the Penfield 3 instrument. Then what's used is what's known as the B1 with footplate to create the bone flap - https://www.researchgate.net/publication/323134344_Exposure_of_Dural_Venous_Sinuses_A_Review_of_Techniques_and_Description_of_a_Single-piece_Troughed_Craniotomy/figures?lo=1 https://www.researchgate.net/publication/323134344_Exposure_... Here is an example of the drill system - Midas Rex MR8 - https://www.ebay.com/itm/125960633809 https://www.ebay.com/itm/125960633809 Here's a video of a surgeon performing the pterional craniotomy, probably the most common craniotomy for things like aneurysms, - https://www.neurosurgicalatlas.com/volumes/cranial-approaches/pterional-craniotomy https://www.neurosurgicalatlas.com/volumes/cranial-approache...