====== 🧠 Posterior Superior Alveolar Nerve (PSAN) ======

🔹 Origin

A branch of the maxillary nerve (CN V2)

Arises in the pterygopalatine fossa

🔹 Course

Leaves the pterygopalatine fossa via small foramina on the posterior wall of the maxilla (called the posterior superior alveolar foramina)

Enters the posterior surface of the maxilla

Travels within the posterior wall of the maxillary sinus, forming a plexus (along with middle and anterior superior alveolar nerves)

🔹 Distribution

Sensory innervation to:

Maxillary molars (except mesiobuccal root of 1st molar—often supplied by the middle superior alveolar nerve)

Buccal gingiva (overlying the maxillary molars)

Mucosa of the maxillary sinus

🦷 Clinical relevance

Often anesthetized during dental procedures on the upper molars

Its proximity to the maxillary sinus explains how dental infections or extractions can sometimes involve the sinus (oroantral communication)

🧠 In the context of the pterygopalatine fossa:

One of the first branches of CN V2 after it enters the fossa via the foramen rotundum

Does not pass through the pterygopalatine ganglion