The axis: this bone (cervical vertebra 2 or "C2"), has the pivotal bony knob called the dens, allowing it to fit with the C1 axis vertebra above it, and allowing our heads to turn!
Great care was taken to model and create it with anatomical accuracy (although it is just a fraction of real life size!), and to show off all the interesting and unique bony structures on this piece of the spine. The knobby part, or the dens, has been purposively shortened to allow this to lay nicely on the neck. The lateral or side loops let this transform nicely into a pendant - slip some findings through, hang horizontally or vertically and attach to your chosen chain! (chain not included.)