Ultrasound-guided maxillary nerve block approaches with probe and needle entry, advancement and redirection
| Needle approach | Ultrasound probe placement | Initial needle entry | Needle advancement | Needle redirection |
| Posterior infrazygomatic, in-plane1 3 | Below zygomatic process, just anterior to mandibular condyle | Posterior to anterior; lateral to medial | Through LPM to area just above LPP | None |
| Anterior infrazygomatic, in plane6 | Below zygomatic process, at the uppermost part of the LPP | Anterior to posterior; lateral to medial | Through LPM into anterior border of top of LPP | Withdrawn and reoriented medially to advance 1–2 mm into PPF |
| Suprazygomatic, out of plane4 7 10 | Below zygomatic process, over the maxilla at 45° of inclination in frontal and horizontal planes | Perpendicular to skin at frontozygomatic angle in suprazygomatic area | The greater wing of the sphenoid was contacted at 20 mm depth | Withdrawn and reoriented and advanced 35–45 mm deep into PPF |
LPM, lateral pterygoid muscle; LPP, lateral pterygoid plate; PPF, pterygopalatine fossa.