Screw

Abstract

An element with a thread is created, in which both partial flanks enclose a negative angle with a plane extending perpendicular to the screw axis. Further, a screw or a hook for connecting to a rod, as used in particular in spinal column surgery, is created, wherein the inner thread of a holder, to which the rod is connected, and the associated thread of a nut comprise the thread according to the invention.

1 . (canceled)  
   
   
       2 . (canceled)  
   
   
       3 . A device comprising: 
 a shank;    a holding component for engaging and holding a rod, the holding component comprising a recess having two legs, a U-shaped cross-section for accommodating the rod, an open end for receiving the rod into the U-shaped cross-section between the legs, and an inner thread on the legs; and a screw, which cooperates with the inner thread and directly or indirectly acts on the rod when positioned in the recess, the screw having a central axis;    wherein the inner thread comprises an inner thread base, first and second partial flanks adjacent to one another, and an internal thread edge between the first and second partial flanks;    wherein the screw has an outer thread for engagement with the inner thread of the legs, the outer thread comprising an outer thread base, third and fourth partial flanks adjacent to one another, and an external thread edge between the third and fourth partial flanks;    the first and third partial flanks, which face away from the open end, enclose a negative angle β 2  with a plane which extends through the respective thread base and extends perpendicular to the central axis;    the second and fourth partial flanks, which face toward the open end, enclose a positive angle β 1  with a plane which extends through the respective thread base and extends perpendicular to the central axis.    
   
   
       4 . The device according to  claim 3 , wherein the internal thread base is rounded between adjacent first and second partial flanks.