Figure 44-20 Anatomic landmarks and method of needle placement for maxillary and mandibular nerve blocks. A, The ophthalmic, maxillary, and mandibular nerves provide sensation to the eye and forehead, midface and upper jaw, and lower jaw, respectively. B, The mandibular and maxillary nerves can be blocked through the same needle entry site. C, A needle is inserted at the inferior edge of the coronoid notch perpendicular to the skin entry site, and after contacting the lateral pterygoid plate, it is withdrawn and redirected anteriorly and superiorly to walk off the plate (arrows). It is advanced approximately 0.5 cm into the pterygopalatine fossa. D, The mandibular nerve is blocked through the same entry site as the maxillary nerve and by the same method, except that the needle is withdrawn and redirected to walk off the posterior border of the pterygoid plate (arrow). When it is advanced to elicit paresthesia, the needle should not be inserted more than 0.5 cm past the plate.