Posterior superior alveolar nerve block. Artwork of a syringe being used to inject a local anaesthetic to numb the posterior superior alveolar nerve, a procedure known as a nerve block. This nerve supplies the three molar teeth of the upper jaw, including the rearmost molar (wisdom tooth). This nerve block allows minor surgery to be carried out on the upper teeth and mouth, including dental work. The injection is applied in the buccal fold between the first and second molars. For the three regions affected by superior alveolar nerve blocks, see C016/6835. For the injections, see C016/6822 to C016/6824.