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Superior Alveolar Nerves

nervi alveolares superiores

The superior alveolar nerves supply the upper dentition and associated gingiva: the posterior superior alveolar nerve (PSAN) from V2 in the pterygopalatine fossa supplies the upper molars and their buccal gingiva; the middle superior alveolar nerve (MSAN, present in 70%) from the infraorbital canal supplies the premolars; and the anterior superior alveolar nerve (ASAN) from the infraorbital canal supplies the anterior teeth. All three form the superior dental plexus.

Region: Head & Skull

Clinical Relevance

Clinical Notes

Understanding the three superior alveolar nerves explains patterns of anaesthesia inadequacy in upper dental procedures. The PSAN is blocked by posterior superior alveolar block for upper molar anaesthesia; the MSAN and ASAN by infraorbital nerve block or direct buccal infiltration. In maxillary sinus surgery, the PSAN branches running within the posterior maxillary sinus wall are divided, producing temporary molar tooth numbness. Le Fort I osteotomy divides all three superior alveolar nerves and produces predictable but temporary upper dental anaesthesia.

Pathology

Common Injuries & Conditions

Superior Alveolar Nerve Disruption in Le Fort I Osteotomy

Le Fort I osteotomy through the lateral maxillary walls and pterygomaxillary fissure divides all three superior alveolar nerve branches, producing complete anaesthesia of all upper teeth and buccal gingiva post-operatively; sensation returns in 85% within 6 months as nerves regenerate through the osteotomy site.