The dens is a conical, tooth-like projection from the superior surface of the axial body. It is approximately 1.5 centimeters long, having a broad base, narrowed central waist, and a tapering apex. The dens projects into the ring-like atlas where it serves as a pivotal axis for this bone.

The Latin dens means tooth. The Greek predecessor to this word is odon. Process is a term used in anatomy to describe a projection on a bone. It comes from the Latin pro- meaning forward and cessus for gone. It is an old term that can be traced back to the writings of the early anatomist Celsus.

Dens axis