Is a skin wheal the best way to place local anesthetic to numb skin?

Is forming a skin wheal the ideal method of anesthetizing skin before performing procedures such as starting IV's or central lines or placing epidural catheters? If so, can you explain the physiological basis?
Is a skin wheal the best way to place local anesthetic to numb skin?
It is a good way because that part of your skin has a lot of nerve endings. However, using lidocaine isn't the only way to deaden the skin. People actually use normal saline injections in the same way and get similar results. The fluid interrupts the transmission of pain signals. I am not sure of the physiology involved, though.





There are also topical creams or gels that can be used that give good results. Emla cream is often used for this purpose. You can also use topical lidocaine that comes in a gel. The downside to the topical applications is that you have to put them on 10 to 30 minutes before the needle stick in order for them to work well. The good part is that, unlike the skin wheal, you don't need an additional stick.