What is the normal size of a 5ml syringe needle?

The normal needle for a 5 ml syringe is a 7-gauge needle with a 3 cm barrel, or a 5-gauge needle with a 3.8 cm barrel.

The usual syringes used are 2 ml, 5 ml, 10 ml, or 20 ml, occasionally 50 ml or 100 ml, and 1 ml syringes for intradermal injections. The syringe barrel may be made of plastic or glass.

And usually have a graduated indication of the volume of fluid in the syringe. Glass syringes can be sterilized in an autoclave, but because plastic syringes are less expensive to handle.

Extended information:

Syringes are also used for medical devices, containers, and in some cases chromatography. Some scientific instruments in chromatography inject through a rubber septum. Injecting gas into a blood vessel will result in an air embolism.

The way to remove air from a syringe to avoid an embolism is to turn the syringe upside down, tap it gently, and then squeeze out a little liquid before injecting it into the bloodstream.

Baidu Encyclopedia - Syringe