Bone anchor for optimised cement application

A bone anchor for the fixation of bone components and bone fragments, comprising a shaft, a neck area and a head located in a proximal direction and a tip located in a distal direction;

• wherein the bone anchor has a mainly cylindrically shaped hollow chamber extending along a central axis;
• wherein the hollow chamber is adjacent a proximal transition zone located proximally from a central plane perpendicular to the central axis;
• wherein the proximal transition zone has an inner diameter and the hollow chamber has an opening diameter;
• and the opening diameter of the hollow chamber is greater than the inner diameter of the proximal transition zone;
• wherein the proximal transition zone defines a section which causes a higher flow resistance compared to a section of the same length of the hollow chamber;
• said section of the proximal transition zone having a ring, wherein an inner surface of the ring defines the inner diameter, the ring is held in said section of the proximal transition zone by support elements in communication with an outer wall of the bone anchor, wherein the ring is located within a concentric radial recess defining a stagnation space with an outer diameter greater than the inner diameter so that the radial recess is formed in a side of said section of the proximal transition zone, and spaces between the support elements, the outer wall, and an outer surface of the ring are configured to divert a flow of fluid therethrough, and said section of the proximal transition zone further comprises a blocking surface element which is located proximal to the stagnation space and is configured to generate a dynamic pressure in a blocking direction.