Posterior superior nasal nerves

The posterior superior nasal nerves, also known as the short sphenopalatine nerves, are branches of the pterygopalatine ganglion. There are lateral and medial branches which supply the nasal cavity.

Gross anatomy

The nerves branch off the maxillary division of the trigeminal nerve (CN V) just after emerging from the foramen rotundum to enter the pterygopalatine fossa. At the pterygopalatine ganglion it receives parasympathetic fibers which supply nasal glands. It leaves the fossa inferomedially through the sphenopalatine foramen with the nasopalatine nerve to enter the posterosuperior nasal cavity just behind the superior nasal meatus where it divides into medial and lateral branches:

• medial branches supply the posterosuperior quadrant of the nasal septum 
• lateral branches supply the posterosuperior quadrant of the lateral nasal wall

Variant anatomy

Occasionally the posterior superior nasal nerves may branch off the nasopalatine nerve either just before or after it passes through the sphenopalatine foramen.