Discussion on:

An innovation we can all cheer: the pain-free needle

If You know where to inject, there is seldom any pain even with an ordinary needle. The secret is: stay away from the bloodvessels, because that's where the nerves are most numerous. And always use a new clean needle, used needles are both dull and a health hazard. Ask any diabetic for more information.

Dukhalon is correct. Also, novocaine, xylocaine or any 'caine that is injected to numb an area burns like a wasp bite. What is uncomfortable (in addition to the blood vessel with nerve wrapped around it and vein alonside) is the volumn of liquid that displaces tissues and puts pressure on the nerve. Having said all that, some injections are just plain painful. Gamma Gobulin tends to make you limp for awhile. Some need to be mixed with other drugs or something called Neut in order to neutralize the acid/base of the injectate. But the bottom line is this, do it fast, avoid areas known to us to be sensitive and move on. Life is hard sometimes we just have to knuckle up. And for years now we have been able to apply painless topical numbing agents before injecting tender young folks.

Anyone that has regular subcutaneous injections and knows anything about how the skin nerve system is laid out - knows that if you inject between the hair follicles and never into their base, you'll have a sensation free injection 9 out 10 times. Hair follicles are rich in sensory nerves - get near them as you inject and you trigger pain - hit one directly and it really hurts. The fact that most doctors and nurses aren't trained with this knowledge tells you a lot about how deficient our medical education system really is - but they do get special courses in how to minimize wasting time with patients and more efficient billing practies.

From a phlebotomist I knew. She actually picked it up from an acupuncturist she was drawing blood from.

Nto shrre whre he pickld in op form, thob.

These mosquito-inspired needles vibrate and are highly serrated which greatly reduces stimulation of the nerves.

http://scopeblog.stanford.edu/2011/03/mosquito_stinge

In the early 70's, the Navy used pnuematic injectors to do most of the immunisation shots. It used compressed air to shoot the vaccine into the skin. Not painless but not the pin prick of a needle. One downside was that occasionally the shot would cause a small tear in the skin and bleed a little. I have not seen or heard if this system is still used.

They worked good unless the corpsman thought he was stamping price tags on canned goods.

The dragging motion is what caused the skin to tear. A straight on shot did no damage.

I saw a captain rip a corpsman a new one after he walked into the clinic and saw a line of guys holding gauss on wounds from shots.