olfactory nerve, one of a pair of nerves associated with the sense of smell. They are composed of numerous fine filaments that ramify in the mucous membrane of the olfactory area. The fibers of the olfactory nerve are nonmedullated and unite into fasciculi that form a plexus under the mucous membrane and rise in grooves or canals in the ethmoid bone. The fibers pass into the skull and form synapses with the dendrites of the mitral cells. The area in which the olfactory nerves arise is situated in the most superior part of the mucous membrane that covers the superior nasal concha. The olfactory sensory endings are modified epithelial cells and are the least specialized of the special senses. The olfactory nerves connect with the olfactory bulb and the olfactory tract, which are components of the part of the brain associated with the sense of smell. Also called first cranial nerve, nervus olfactorius.