Abstract: A needle assembly includes an elongate needle mount (10), a needle (12), and a sheath (14) mounted on the elongate needle mount (10) for reciprocal axial movement between a forward position whereat the sheath (14) covers the needle (12) and a rearward position whereat the needle (12) is exposed.

Abstract: A single use syringe (10) includes a needle (18), barrel (16), plunger assembly (20) and shield (12). The barrel (16) bears a locking member (26) which encircles the front end of the barrel (16) and is carried forward by the barrel (16) to a position where it engages the shield (12) and is retained by the shield (12) such that the locking member (26) is separated from the barrel (16) as the barrel (16) is withdrawn rearwardly after use. The locking member (26) is resilient and, after it is removed from the barrel (16), assumes a configuration which prevents subsequent forward movement of the barrel (16) within the shield (12). The barrel includes a frangible seal (30) which is broken by rearward movement of needle mount (32). The shield (12) includes a shield extender (14) for controlling the depth of penetration of the needle. The syringe can also be used to inject medicament into a IV bag via a male port as shown in FIG. 7.