What is the depth of penetration for a greater palatine nerve block?

• A. <5 mm or until palatine bone is contacted
• B. 5-10 mm
• C. 10-15 mm
• D. Until soft tissue resistance is exhausted

Answer: (A)

Shallow depth is the determining factor here because the greater palatine nerve sits right at the palatine bone near the greater palatine foramen. You want the needle to reach the nerve’s vicinity without going deeper, so you advance only until you contact the palatine bone. That bone contact typically occurs at less than 5 mm of insertion, which is why the recommended depth is “less than 5 mm or until palatine bone is contacted.”

Going deeper, such as 5–10 mm or 10–15 mm, would place the anesthetic away from the nerve and could waste the injection or increase risk of tissue trauma. The idea of injecting until soft tissue resistance is exhausted isn’t appropriate here because the goal is to reach the area near the nerve by contacting bone, not to push through all soft tissue.