Screw for fixing atlantoaxial joint

摘要

A screw fixing an atlas to an axis, wherein a cutter portion (13) is provided at one end of the screw (12) which has a through-hole (17) in the shaft center, and cutting edge part of cutter portion (13) comprises a pair of facing protrusions (20) formed by a pair of inclined planes (18,19) and a pair of taper faces (21), such that said protrusions (20) form cutter blades (13A).