Cadaveric Study for Intraoral Needle Access to the Infratemporal Fossa: Application to Posterior Superior Alveolar Nerve Block Technique

The posterior superior alveolar (PSA) nerve block is, from an anatomical perspective, challenging because the mandibular ramus and the zygomatic process of the maxilla can interfere with the course of the needle. Dentists empirically know that shifting the patient's mandible to the ipsilateral side can improve visibility and accessibility for such blocks. This cadaveric study aimed to establish anatomical evidence for the ipsilateral mandible shifting used in the PSA. The distance between the lateral most bulging point of the alveolar part of the maxilla and ipsilateral anterior border of the ramus of the mandible ranged from 1.4 to 6.9 mm with a mean of 4.3 ± 1.6 mm. This result supports the empirical technique of shifting the mandible ipsilaterally for PSA nerve block.