What is the typical injection volume for the greater palatine canal approach?

• A. 1.8 mL
• B. 0.5 mL
• C. 3.0 mL
• D. 2.0 mL

Answer: (A)

The amount of anesthetic needed for the greater palatine canal approach is determined by filling the canal enough to bathe the greater palatine nerve as it runs along the canal from the foramen toward the posterior palate. This nerve supplies the palatal mucosa and associated tissues posterior to the canine area, so a small, precise amount must reach the nerve within the canal without overdistending the palatal tissues.

About 1.8 mL is the typical volume because it provides sufficient solution to fill and bathe the nerve along the canal, achieving reliable anesthesia of the posterior palatal region. Injecting too little (for example, a very small amount) risks incomplete blockade, while injecting much more (like 3.0 mL) can increase tissue distention and the chance of unwanted spread or discomfort. A volume around 2.0 mL is close to this range, but 1.8 mL aligns with common recommended practice for this approach.