Which injection carries the risk of hitting the pterygoid plexus if the needle is advanced too far?

Which injection carries the risk of hitting the pterygoid plexus if the needle is advanced too far?

• A. Posterior Superior Alveolar
• B. Infraorbital
• C. Inferior Alveolar
• D. Greater Palatine

Answer: (A)

The key idea is that certain maxillary injections pass near the infratemporal fossa where the pterygoid venous plexus sits. During a posterior superior alveolar block, the needle is directed toward the posterior maxilla near the PSA foramina. The pterygoid venous plexus lies just behind the maxilla and around the PSA vessels, so advancing the needle too far can puncture these veins and cause a hematoma or vascular entry. That close relationship between the PSA region and the pterygoid plexus makes this injection the one with the highest risk of hitting the plexus. In contrast, an infraorbital injection travels anteriorly through the infraorbital canal, the inferior alveolar approach targets the mandibular canal, and a greater palatine injection goes through the palatine region. These paths are not in the same infratemporal vicinity as the pterygoid plexus, so they don’t carry the same risk of encountering it.

The key idea is that certain maxillary injections pass near the infratemporal fossa where the pterygoid venous plexus sits. During a posterior superior alveolar block, the needle is directed toward the posterior maxilla near the PSA foramina. The pterygoid venous plexus lies just behind the maxilla and around the PSA vessels, so advancing the needle too far can puncture these veins and cause a hematoma or vascular entry. That close relationship between the PSA region and the pterygoid plexus makes this injection the one with the highest risk of hitting the plexus.

In contrast, an infraorbital injection travels anteriorly through the infraorbital canal, the inferior alveolar approach targets the mandibular canal, and a greater palatine injection goes through the palatine region. These paths are not in the same infratemporal vicinity as the pterygoid plexus, so they don’t carry the same risk of encountering it.