Abstract: A medullary rotational reaming apparatus includes an elongated, flexible, hollow, tubular shaft formed of a nickel-titanium alloy and having coupling portions at the opposite ends thereof. Each of a cutter head and a rotational drive coupling element has a hollow tubular coupling shank, each shank having a coupling inner surface which is quadrilobular in transverse cross section and is dimensioned to prevent free reception of a coupling portion of the shaft therein. The coupling portions of the shaft are axially press-fitted in permanent engagement, respectively, within the shanks of the cutter head and the drive coupling element, with said coupling portions being permanently deformed to the transverse cross section of the coupling inner surface of the shanks, thereby to fix the cutter head and the coupling element to the shaft solely by the press-fitted engagement of the coupling portions in the shanks.