Harpoon of the anesthetic syringe must engage so that aspiration can occur during the injection.
To create the necessary negative pressure for aspiration, these syringes rely on the elasticity of the anesthetic cartridge's rubber diaphragm. A metal projection within the syringe that sends the needle into the cartridge supports the diaphragm.
In the pulp chamber and the root canal, a short 27-gauge needle is securely lodged. The local anesthetic is injected in a very tiny amount (0.2 to 0.3 mL).
One end of the cartridge's rubber stopper is engaged by the harpoon on the aspirating syringe's plunger. The needle can pierce the rubber diaphragm and enter the anesthetic cartridge.
to learn more about syringe visit:
https://brainly.com/question/20320556
#SPJ4
