(EN) A hypodermic syringe (1) is provided having a barrel (5) with a movable plunger (7) therein to inject a fluid through a hollow needle thereof which is housed within a passageway of a needle assembly that is attached to the barrel by ultrasonic welding means or other permanent attaching means. Positioned between sacrificial supports (31) in the needle assembly and the barrel is a deformable base (11). The deformable base houses an enlarged head (13) of the needle which is in contact with energy storage means (21) within the passageway of the needle assembly. The plunger has a rupturable boot (43) thereon which, upon completion of an injection, contacts a deformable base forcing it downward and severing a sacrificial support means within the needle assembly thereby permitting the base to move the enlarged head of the needle downward, until it is blocked by the passageway. Further movement of the base forces the enlarged needle head from the base and into contact with the rupturable boot.
