Which region is primarily targeted by a PSA nerve block?

• A. Maxillary molars region
• B. Mandibular molars region
• C. Anterior maxillary teeth only
• D. Palatal soft tissue only

Answer: (B)

The PSA nerve block targets the maxillary molar region. The posterior superior alveolar nerve supplies the roots and buccal gingiva of the maxillary molars (and often the mesiobuccal root of the first molar), so injecting to anesthetize this nerve will numb the upper jaw’s molar area and surrounding cheek tissue. It does not affect the mandible, since the mandibular molars are innervated by the inferior alveolar nerve (a branch of V3). It also doesn’t primarily anesthetize the anterior maxillary teeth or palatal soft tissue, which are supplied by other nerves (anterior superior alveolar for the front teeth and the greater palatine/nASOPALatine nerves for the palate). Therefore, the region most specifically targeted by a PSA nerve block is the maxillary molars region.