Bone screw
A medical screw, including: a first region comprising a constant diameter first root having a first diameter and a constant pitch multi-start thread; a second region forming a transition region; and a third region including a constant diameter root having the first diameter and a constant pitch thread, wherein the transition region is in between the first region and the second region and joins the first region with the second region, and wherein a lead of the constant pitch multi-start thread is different from a lead of the constant pitch thread.
1 . A medical screw, comprising:
a first region comprising a constant diameter root with a first diameter and a constant pitch thread;
a second region comprising a constant diameter root with the first diameter and a variable thread pitch that joins continuously to the constant pitch thread; and
a third region having a tapered root with a tapered diameter and a variable pitch thread that joins continuously to the variable pitch thread of the second region;
wherein the second region comprises more than one turn of the thread with a variable thread pitch;
wherein the screw is a single threaded screw.
2 . The medical screw of claim 1 , further comprising a cutting tip on the first region.
3 . The medical screw of claim 1 , further comprising a driving feature on the third region.
4 . The medical screw of claim 1 , wherein the first region is a distal region and is adjacent the second region at one end thereof.
5 . The medical screw of claim 4 , wherein the third region is a proximal region and is adjacent the second region at the other end thereof.
6 . The medical screw of claim 4 , wherein a largest root diameter in the third region is greater than or equal to an outer diameter of the constant pitch thread in the first region.