Local anaesthetic is deposited around the nerve proximal to the site that you want to anaesthetise. The injection site may at some distance from the operative field.

For example, in the inferior alveolar block injection (inaccurately called the mandibular block), local anaesthetic solution is deposited around the inferior alveolar nerve in the infratemporal space before it enters the intrabony mandibular canal. This way, pulpal anaesthesia is achieved for all the ipsilateral mandibular teeth. Soft tissue anaesthesia includes the lip, and buccal tissues of teeth anterior to the second premolar.