There are four primary areas in the neurocranium: the occipital, orbitotemporal, otic and ethmoidal regions.
It exits into the nasal cavity to supply posterior ethmoidal cells and nasal septum; here it anastomoses with the sphenopalatine artery.
The ethmoidal air cells consist of numerous thin-walled cavities situated in the ethmoidal labyrinth and completed by the frontal, maxilla, lacrimal, sphenoidal, and palatine bones.
It carries sensory information from the sphenoid sinus and posterior ethmoidal air cells.
It is the thinnest wall of the orbit, evidenced by pneumatized ethmoidal cells.
Lateral to either olfactory groove are the internal openings of the anterior and posterior ethmoidal foramina (or canals).
The anterior ethmoidal foramen, situated about the middle of the lateral margin of the olfactory groove, transmits the anterior ethmoidal artery, vein and nerve.
The nerve is the continuation of the nasociliary nerve after it enters the anterior ethmoidal foramen into the anterior ethmoidal air cells.
