Safety syringe

A method for injecting, comprising:

• providing a system, the system comprising
• a syringe body having proximal and distal ends, and a syringe interior,
• an injectable fluid in the syringe interior,
• a stopper member disposed in the syringe interior,
• a plunger member coupled to the stopper member, and
• a needle assembly coupled to the distal end of the syringe body, the needle assembly comprising
• a needle housing,
• a O-ring disposed in the needle housing such that, when the needle assembly is coupled with to the distal end of the syringe body, the distal end of the syringe body is in contact with the O-ring, and
• a needle removably coupled to the needle housing by the O-ring such that the O-ring limits movement of the needle along a longitudinal axis of the needle assembly, the needle comprising
• a needle sleeve having a circumferential notch formed thereon, and
• a distal needle portion;
• compressing the O-ring between the distal end of the syringe body and an interior surface of the needle housing, such that the O-ring squeezes an outer surface of the needle;
• inserting the stopper member distally in the syringe interior to inject the injectable fluid from the syringe interior through the needle;
• triggering retraction of the needle inside of the syringe body by moving the stopper member to the distal end of the syringe body;
• and
• when the stopper member has been inserted to the distal end of the syringe body, retracting the needle inside of the syringe body.