A method for manufacturing an elongated element (200) is provided. The method comprises arranging a molding cavity (101), defined by a mold (103) and a mold insert (104), said mold insert (104) comprising a mold core (105) and a displaceable mold cavity wall (106), said displaceable mold cavity wall (106) being arranged between the mold (103) and the mold core (105), such that the molding cavity has a start volume in a start position of the displaceable mold cavity wall (106). Then a liquid material is injected into a proximal end (102) of the molding cavity (101), where after the displaceable mold cavity wall (106) is displaced in relation to and along with the mold (103) and the mold core (105), distally during said injection, to increase the molding cavity volume from the start volume into an end volume at an end position of the displaceable mold cavity wall (106), wherein the molding cavity (101) in said end position of the displaceable mold cavity wall (106) corresponds to the elongated element (200). The liquid material is solidified, such that the elongated element (200) is formed, and the elongated element (200) and mold insert (104) is removed from said mold (103), where after the elongated element (200) is removed from said mold insert (104). An elongated element and a mold assembly for the manufacture thereof are also provided.Linvention décrit un procédé de fabrication dun élément de forme allongée (200). Le procédé comprend létape consistant à disposer une cavité de moulage (101), définie par un moule (103) et un insert de moule (104), ledit insert de moule (104) comprenant un noyau de moule (105) et une paroi de cavité de moulage mobile (106), ladite paroi de cavité de moule mobile (106) étant disposée entre le moule (103) et le noyau de moule (105), de telle sorte que la cavité de moulage a un volume de départ dans une position de départ de la paroi de cavité de moule mobile (106). Ensuite un matériau liquide est injecté dans une extrémité proximale (
