Posterior ethmoidal nerve

The posterior ethmoidal nerve is a nerve of the head. It is a branch of the nasociliary nerve (itself a branch of the ophthalmic nerve (CN V1)). It provides sensory innervation to the sphenoid sinus and ethmoid sinus, and part of the dura mater in the anterior cranial fossa.

Origin
The posterior ethmoidal nerve is a branch of the nasociliary nerve.

Course
It passes through the posterior ethmoidal foramen alongside the posterior ethmoidal artery.

Branches
Within the anterior cranial fossa, it issues a branch to which innervates part of the dura mater.

It gives branches to the sphenoid sinus and the ethmoid sinus.

Variation
The posterior ethmoidal nerve is absent in a significant proportion of people. This may be around 30%.

Function
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.

Other animals
The posterior ethmoidal nerve is present in other animals, including horses. Headshaking can sometimes be treated with analgesia or neurectomy of the posterior ethmoidal nerve.