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US 5,375,956 AGranted
Head screw construction for use in fixing the position of an intramedullary nail
OwnerDietmar Penniginventor
Life of this patent
Estimating the term…
Abstract
The invention relates to a screw for fixing an intramedullary nail in position. An external thread on the screw shank is provided over only a part of the length of the shank. The screw head is provided with an external thread having a direction of helical advance which is opposite the direction of helical advance of the screw-shank thread.
Claims12
A headed screw (1) with a bone-engaging screw thread, comprising an elongate shank (3) having an external thread (4) for bone-engaged anchorage of said screw (1), and a drive head (2) at one end of said shank (3), wherein:
- (a) the shank thread (4) is close to said head (2) and extends for only a portion of the length of said shank (3);
- (b) the head (2) has a key formation that is externally accessible for selective rotation of the headed screw (1) in a first direction of advancing screw-thread engagement in bone;
- and
- (c) the head (2) has an external thread (5) having a direction of thread advance which is opposite to the direction of shank-thread (4) advance.
1 more element
Dependencies are inferred from the claim text.