Abstract: An alignment device is provided for an artificial limb and comprises first and second end plates fastenable to respective upper and lower parts of the limb in a predetermined angular and axial position. A flexible sleeve fastened between the end plates forms therewith an internal cavity for containing a body of settable fluid. When the fluid body is in a flowable state relative movement between upper and lower parts of the limb during alignment thereof are accommodated by flexion of the sleeve. When the fluid body is in a solidified state it establishes a rigid mechanical linkage between the end plates, thereby preventing relative movement of the upper and lower parts. Angular alignment between an end plate and an adjoining part of the limb is provided by pegs on one of said parts engaging sockets on the other of said parts.