Patent ID: 9737338
Date: 2017-08-22
CPC Classifications: A61B

Claim:
1. A polyaxial bone anchoring system comprising: a bone anchoring element provided with a hemispherical head, a tubular barrel for coupling a stabilizing element with the bone anchoring element, said tubular barrel comprising a tubular barrel body having a lower opening end and an opening upper end, means for locking the bone anchoring element in the tubular barrel, said locking means being situated inside the tubular barrel body, and a conical split ring, said tubular barrel body comprising a base which an axial channel having a cross-section greater than a cross-section of the hemispherical head goes through, with said axial channel having a frustoconical housing which widens in the direction opposite to the lower opening end of the tubular barrel body, said tubular barrel body comprising a transverse shoulder having an inner cross-section substantially equal to the cross-section of the hemispherical head, said transverse shoulder delimiting with the lower opening end of the tubular barrel the frustoconical housing said conical split ring having an outer surface matching the inner surface of the frustoconical housing of the barrel body and having a minimum cross-section, when idle, which is smaller than the cross-section of the hemispherical head, with said ring being made of a material which is deformable between an expanded position allowing the passage of the hemispherical head through the split ring and a retracted position having a cross-section smaller than the minimum cross-section, when idle, for the insertion thereof into the frustoconical housing, with the frustoconical housing having a height greater than the height of the split ring and, around the shoulder, a cross-section greater than the outer cross-section of the ring, wherein said frustoconical housing comprises, a radial groove situated around the transverse shoulder.