1. The special needle used to deliver the injection is held in the needle hub.
2. The special hook on the tip of the plunger is specially designed to engage the needle hub.
3. The final movement of the plunger, at the end of drug delivery, enables the hook to “grab” the needle.
4. Retraction of the plunger withdraws the needle safely back into the barrel.
5. After retraction the needle falls to the side within the barrel, preventing re-deployment.
6. Once the needle is fully inside the barrel, the plunger is broken off, preventing re-use of the syringe. |