What kind of local anesthesia is deposited close to a main nerve trunk, usually at a distant site from the site of operative innervation?

• A. Nerve block
• B. Field block
• C. Local infiltration
• D. Topical anesthesia

Answer: (A)

Blocking a main nerve trunk is about delivering anesthetic where the nerve travels, not right at each tooth. When you deposit near the trunk, you interrupt all the fibers traveling in that nerve, so a large area—often multiple teeth and surrounding tissues supplied by that nerve—becomes numb. The injection is typically placed away from the exact operative site, which is why you can achieve broad anesthesia with a single dose. This contrasts with local infiltration, which numbs only a small, tooth-by-tooth area by injecting right around the tooth; a field block aims to numb a wider region along a nerve pathway but is still applied closer to the operative area; topical anesthesia affects only the surface mucosa.