This device was secured around the top of the head, much like the medical 'halo' device of today. The single or double screws were slowly tightened, driving the spikes into the side of the skull.
Some examples had handles on the sides, allowing the torturer to jerk the victim from side to side.
The device could be used to provide excruciating pain, or in the extreme, the victim could be hoisted into the air, resulting in removal of the top of the cranium or breaking of the cervical vertebrae.
There is a Scottish beer named "Skull Splitter"
, although it is actually named after Thorfinn Hausakluif (Skullsplitter)
rather than the torture device.