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Olfactory nerve (CN I)

Dr Frank Gaillard et al.

The olfactory nerver (CN I) is the first and most rostral of the cranial nerves.

Along with the optic nerve, it is really a peripheral outpost of the central nervous system. The bipolar first order sensory cell is located in the neuroepithelium in the roof of the nose, immediately inferior to the cribiform plate of the ethmoid bone. This cell is analogous to the senory cells of spinal nerves, whose cell bodies reside in the dorsal root ganglion. Their central processes form filaments which pass through the cribiform plate, pierce the dura mater and relay in the olfactory bulb. The central process of these second neurons pass via the olfactory tracts (located in the olfactory grooves of the anterior cranial fossa, to enter the perforated substance and uncus.