Structure
- The posterior ethmoidal nerve is a branch of the nasociliary nerve.
- It passes through the posterior ethmoidal foramen alongside the posterior ethmoidal artery.

Innervation
- Within the anterior cranial fossa, it issues a branch to innervate part of the dura mater.
- It gives branches to the sphenoid sinus and the ethmoid sinus.
- The posterior ethmoidal nerve supplies sensation to the sphenoid sinus and the ethmoid sinus.
- It also supplies sensation to part of the dura mater in the anterior cranial fossa.

Variation
- The posterior ethmoidal nerve is absent in around 30% of people.
- This absence may affect the innervation of the sphenoid sinus and the ethmoid sinus.

Other animals
- The posterior ethmoidal nerve is present in other animals, including horses.
- Analgesia or neurectomy of the posterior ethmoidal nerve can be used to treat headshaking in horses.

References
- Barral, Jean-Pierre; Croibier, Alain (2009). Manual Therapy for the Cranial Nerves. Churchill Livingstone. pp.115–128.
- Semmer, A. E.; McLoon, L. K.; Lee, M. S. (2010). Orbital Vascular Anatomy. Encyclopedia of the Eye. Academic Press. pp.241–251.
- Shimizu, Toshihiko; Suzuki, Norihiro (2010). Handbook of Clinical Neurology. Vol.97. Elsevier. pp.35–45.
- Seker, Askin; Martins, Carolina; Rhoton Jr., Albert L. (2010). Meningiomas. Saunders. pp.11–51.
- Rea, Paul (2016). Essential Clinically Applied Anatomy of the Peripheral Nervous System in the Head and Neck. Academic Press. pp.21–130.