Posterior ethmoidal nerve

The posterior ethmoidal nerve is an extraconal branch of the nasociliary nerve, a branch of ophthalmic division of the trigeminal nerve. It branches off proximal to the infratrochlear nerve and courses through the medial aspect of the extraconal space of the orbit. It exits the orbit through the posterior ethmoidal foramen to supply the mucosa of the sphenoid and posterior ethmoidal sinuses.