Abstract: A syringe with a body and a needle at one end and an injection plunger movable into the body at the opposite end. A guide lug is fixed on the syringe body near the needle end. A sheath is positioned over the syringe body with a longitudinal groove that engages the guide lug. The sheath is movable with respect to the syringe body and guided by the lug so that it can selectively cover or expose the needle while not impeding use of the syringe.