During injection at the INCISIVE FORAMEN (nasopalatine block), all of the following may be anaesthetised EXCEPT:

Correct answer: D. The greater palatine nerve

• A. Solution tracking superiorly up the incisive canal can reach the anterior FLOOR OF THE NASAL CAVITY and the anterior nasal septum, which the nasopalatine nerve also supplies on its course.
• B. The ANTERIOR HARD PALATE mucosa from canine to canine is precisely the field this block is intended to anaesthetise.
• C. The NASOPALATINE nerve is the direct target of this injection — it descends through the incisive canal to supply the anterior palate.
• D. CORRECT — this is the exception. The GREATER PALATINE NERVE emerges from the greater palatine foramen at the POSTERIOR hard palate, near the second or third molar, and supplies the posterior palatal mucosa back from the canine region. It is anaesthetised by a separate greater palatine injection and lies too far posterior to be reached by solution deposited at the incisive foramen.

Note: The nasopalatine block is notoriously the most PAINFUL injection in dentistry, because the palatal mucosa is tightly bound down to periosteum with no space for the solution to expand. Reduce the discomfort by applying topical anaesthetic with pressure for a full minute, using firm pressure with a mirror handle adjacent to the site, approaching alongside the papilla rather than through its centre, and injecting very slowly with minimal volume.