The nasopalatine nerve divides off the maxillary division just after emerging from the foramen rotundum to enter the pterygopalatine fossa. At the pterygopalatine ganglion receives parasympathetic fibers which supply the nasal and palatine mucosal glands as well as special sensory fibers (taste) for the which arrive at the ganglia via the greater petrosal nerve.
It leaves the fossa inferomedially through the sphenopalatine foramen with the posterior superior nasal nerves to enter the nasal cavity just behind the superior nasal meatus where it passes along the roof of the nose and into the nasal septum, where it may groove the vomer. Here is supplies the posteroinferior nasal septum. It continues coursing anteroinferiorly in the nasal septum to enter the incisive canal, then passes through the incisive foramen, entering the roof of the mouth. Here it supplies the anterior hard palate and the gingiva behind the two maxillary incisor teeth.
The left nasopalatine nerve can pass through the anterior incisive foramen and the right nasopalatine nerve can pass through the posterior incisive foramen when an anterior and posterior foramen exists for the incisive foramen.
The posterior superior nasal nerves may branch of the nasopalatine nerve just before or after it passes through the sphenopalatine foramen.