Injecting anesthetic into a small, isolated area at the end of a nerve branch is referred to as what?

Injecting anesthetic into a small, isolated area at the end of a nerve branch is referred to as local infiltration. This technique involves administering the anesthetic directly into the tissue around the area that requires anesthesia, allowing for a localized effect. This is typically done for minor procedures where only a small area needs to be anesthetized, such as in dental work when a specific tooth or region is being treated.

In contrast, nerve blocks involve injecting anesthetic near a large nerve or group of nerves to provide anesthesia to a broader area. Field blocks cover a larger area than local infiltration and involve multiple injections in a defined area. Site blocks, while similar, generally refer to a technique used in specific locations or designated sites, often used for surgical purposes. Local infiltration is thus the most appropriate term for the technique described in the question, as it specifically focuses on treating a confined area effectively.