Abstract: A guide assembly for performing a biopsy with a biopsy device having an elongated and substantially hollow cylindrical barrel is described. The guide assembly includes a bracket which is selectively movable relative to a base. The bracket has a longitudinal opening formed through a housing portion of the bracket into which the biopsy device may be mounted for guiding the biopsy device into desired tissue.

Abstract: A base is provided and a rotor is journaled from the base for rotation about a first upstanding axis. The rotor includes a plurality of vanes journaled therefrom for rotation about second axis spaced about and radially outwardly from the first axis and vane displacement control structure is operatively connected between the base and the vanes for proportionally angularly displacing the vanes relative to the rotor 180.degree. in one direction during each 360.degree. of rotation of the rotor in the opposite direction. The vanes are angularly displaced in optimum positions relative to the rotor and each other to develop maximum thrust by the vanes on the rotor responsive to fluid flow against the vanes from a predetermined side of the first axis.