The anchor member (1) comprises an anchoring base (2) including a peripheral proximal wall (5) that inwardly delimits a proximal cavity, and a proximal stud (3) including a distal articulation portion (7) received in said proximal cavity, said proximal wall (5) including a peripheral proximal rim (6) ensuring retention of said distal articulation portion (7) in that proximal cavity. According to the invention, -the distal articulation portion (7) has a peripheral edge dimensioned to come into the immediate vicinity of the inner surface of said proximal wall (5), and has a convex distal surface (9) whereof the apex is situated substantially at the axis of the proximal stud (3) and -the anchor member (1) comprises an elastically deformable element (10) placed in the bottom of said proximal cavity, having a curved shape whereof the apex is situated substantially at the axis of said proximal cavity, the surface (9) bearing against this element (10), and the latter being permanently elastically deformed such that it continuously presses said portion (7) against said rim (6)Lélément dancre (1) ci-décrit comprend une base dancrage (2) comportant une paroi proximale périphérique (5) qui délimite vers lintérieur une cavité proximale, et un goujon proximal (3) comprenant une partie articulation distale (7) logée dans ladite cavité proximale. La paroi proximale (5) présente une arête proximale périphérique (6) garantissant la rétention de la partie articulation distale (7) dans la cavité proximale. Selon linvention, la partie articulation distale (7) comporte une arête périphérique dimensionnée pour arriver au voisinage immédiat de la surface intérieure de ladite paroi proximale (5), et ayant une surface distale (9) convexe dont lapex se trouve sensiblement sur laxe du goujon proximal (3). Lélément dancre (1) selon linvention comprend en outre un élément à déformation élastique (10) qui se trouve au fond de ladite cavité proximale, ayant une forme incurvée dont lapex se trouve
