Which type of injection is used to anaesthetize the trunk of a nerve?

The correct choice for anaesthetizing the trunk of a nerve is the block injection. This technique involves administering the anesthetic agent near a major nerve or group of nerves, allowing a larger area of the body to be numbed compared to a local infiltration. By specifically targeting the nerve trunk, a block can provide effective pain relief for more extensive procedures or for conditions affecting the specific distribution of that nerve.

Local infiltration typically involves injecting the anesthetic directly into the tissues at the site of the surgical procedure, which is suitable for smaller areas but may not effectively numb a larger or deeper structure provided by a major nerve trunk. Topical anesthesia is used to numb the surface of the skin or mucous membranes and is not effective for deeper structures like nerve trunks. Intravenous sedation is a method to relieve anxiety and sedation for a dental procedure but does not provide localized pain relief since it does not target specific nerves. Thus, the block injection is the preferred method for achieving anaesthesia at the trunk of a nerve.