The present invention relates to a protective sheath (100) for a cannula (210) arranged on a hub (200) which can be fitted onto a syringe (300), said sheath comprising female means intended to cooperate with male means (201) of the hub (200) for guiding thereof, and characterized in that said female means comprise a retracted position before use RBU, a retracted position during use RU, and a retracted position after use RAU, wherein the whole length of the cannula (210) is inside said sheath (100), said female means further comprise an ejection position E, wherein whole or part of the cannula (210) protrudes out of said sheath (100), and further characterized in that at least two of the RBU, RU, and RAU positions are substantially transversally aligned.
