The present invention provides a sheath (60) for at least removably covering the blunt end (28) of the cannula (22). The sheath (60) allows the cannula (22) to be presterilized and utilized without subsequent sterilization. The sheath (60) comprises a body member defining an interior (69) for receiving at least a portion (61) of the blunt cannula (28), the body member including a first end (62) and a second end (66), the first end having an opening (64) for receiving at least a portion of the cannula. The second end (66) including a wall member (80) so constructed and arranged as to rip upon the exertion of a sufficient perpendicular force by an end (28) of the blunt cannula (22). The body also includes sidewalls (68) extending between the first end (62) and second end (66), the sidewalls are so constructed and arranged so as to slide back along the cannula toward the first end (62) upon the tearing of the second end (66) by the cannula and the application of a sufficient force upon the sidewalls.