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.