The posterior superior alveolar nerve (PSAN) is a major sensory branch of the maxillary division of the trigeminal nerve. A PSAN block is a dental nerve block used for profound anesthesia of the maxillary molars. Complications arising from the PSAN block include hematoma formation, transient diplopia, blurred vision, and temporary blindness. This article presents a case of temporary paresis in the lateral pterygoid muscle following a PSAN block that utilized a 27-gauge long needle. The anatomical parameters and pathogenesis of such a complication are reviewed.