Anchor for medical use, intended to be inserted into a bony wall, comprising two parts (2, 3) that are to be assembled, i.e., an outer part, intended to be fastened to the bone, which forms an inner longitudinal cavity through it, and an inner part, intended to be inserted and held in said cavity of the outer part, which forms a transverse conduit passing all the way through it; at least one suture thread being intended to be engaged in said cavity through the proximal side of the outer part, to be engaged through said transverse conduit and to emerge from said outer part, through said proximal side; wherein: - the outer part forms at least one first jamming surface arranged in the longitudinal direction of the outer part and the inner part forms at least one second jamming surface located on the proximal side relative to the transverse conduit that it comprises, this second jamming surface being arranged in the longitudinal direction of the inner part; said at least one suture thread is intended to extend along said first jamming surface and along said second jamming surface; the inner part is movable relative to the outer part between a distal position not blocking the suture thread, in which said second jamming surface is at a distance from said first jamming surface not performing any jamming of this thread, and a proximal blocking position of the suture thread, in which said second jamming surface is at a distance from said first jamming surface performing jamming of this thread.; said outer part forms at least a first engagement surface, separate from said first jamming surface, said inner part forms at least one second engagement surface, separate from said second jamming surface, these respective engagement surfaces (15a, 20a) mutually engaging in said proximal blocking position and immobilizing said inner part relative to said outer part in this position.; characterized in that said outer part and said inner part have respective means (18, 27) for angular positioning of said inner part in said outer part, placing said transverse conduit of the inner part in a determined angular position relative to the outer part; said outer part has a female conical cavity in which two diametrically opposite conduits are arranged, for passage of the strands of the suture thread(s) intended to be connected to the anchor; these conduits are arranged over a diameter that is parallel to the axis of said transverse conduit when said inner part is in said determined angular position; the walls delimiting these conduits on the radially outer side of the outer part forms said first jamming surfaces; the surfaces delimiting said female conical cavity between these conduits form two said first engagement surfaces; said inner part has a male frustoconical portion from which two diametrically opposite bosses protrude; these bosses are arranged over a diameter parallel to the axis of said transverse conduit; these bosses are intended to engage in said conduits during the movement of said inner part from said distal nonblocking position to said proximal blocking position, and to jam the strands of the suture threads between them and said walls delimiting the conduits toward the outside in the radial direction; the bosses make up said second jamming surfaces, and the surfaces of said male frustoconical portion located outside these bosses form two said second engagement surfaces, intended to engage with said first engagement surfaces in said proximal blocking position.. - the outer part forms at least one first jamming surface arranged in the longitudinal direction of the outer part and the inner part forms at least one second jamming surface located on the proximal side relative to the transverse conduit that it comprises, this second jamming surface being arranged in the longitudinal direction of the inner part;