Medical injection system includes automatic injection system needle guard (104) and (102). Needle guard is provided with a carrier that is configured to hold a dose (106), and a plunger medical cartridge having a needle and includes a cartridge housing coupled to the release mechanism. What is connected to the release mechanism and the cartridge housing and a shield, which covers the needle substantially extended position and is configured to extend between the extended position and the position retracted. The release mechanism is configured to allow extension of the shield when it engages and holds in position to the retracted shield. Automatic injection system is configured to inject the dose when it is activated and houses the needle guard. Automatic injection system includes a drive system that engages the pressing vital activate when the plunger.
