Which statement correctly describes the greater palatine canal approach to maxillary nerve block?

Which statement correctly describes the greater palatine canal approach to maxillary nerve block?

• A. Insert soft tissue directly over the GP foramen; deposit 1.8 mL over 1 minute; insert the needle 30 mm and aspirate in two planes; If resistance is felt, withdraw and advance at a different angle
• B. Inject near the GP foramen only
• C. Use a short needle of 5 mm
• D. Do not aspirate during injection and deposit 0.5 mL

Answer: (A)

The key idea here is delivering anesthesia by guiding the needle through the greater palatine canal to reach the maxillary nerve in the pterygopalatine fossa. To do this effectively, you place the needle through the soft tissue over the greater palatine foramen, advance about 30 mm into the canal, and deposit a substantial but controlled amount of anesthetic—about 1.8 mL—over roughly a minute to allow diffusion to the maxillary nerve before it branches. Aspiration in two planes is essential to check for intravascular placement in different directions as you progress, which helps prevent intravascular injection. If you feel resistance, withdrawing a bit and redirecting the needle angle keeps you within the canal path rather than pushing into bone or drifting off target. This combination—approach through the greater palatine canal to the pterygopalatine fossa, a long needle, correct volume delivered slowly, and careful aspiration with angle adjustment—best matches how this block is properly performed.

Injecting near the foramen alone would not position the anesthetic where the maxillary nerve lies, so it wouldn’t reliably block the nerve. Using a very short needle cannot reach the canal. Not aspirating and delivering only a small amount undermine both safety and efficacy of the block.