Abstract: The instrument comprises an outer tube (1) fixed to the end of a flexible sheath (2), and an inner tube (3) displaceable in the outer tube and equipped with a head (5), to which is fixed a cylindrical casing (7) which has an inner boss (15). Arranged inside this casing are blades (10, 11) which are held axially on the outer tube by means of a collar (14) and which can swivel on the outer tube, this swiveling being ensured by the cylindrical casing (7), to be more precise by its end and by its inner boss (15) acting as a cam. This instrument, which is particularly robust, is intended for the removal of deposits formed on the inner walls of the arteries or veins.