| first cranial nerve | Collective term denoting the numerous olfactory filaments: slender fascicles each composed of the thin, unmyelinated axons of 8 to 12 of the bipolar olfactory receptor cells in the olfactory portion of the nasal mucosa; the olfactory filaments pass through the cribriform plate of the ethmoid bone and enter the olfactory bulb, where they terminate in synaptic contact with mitral cells, tufted cells, and granule cells. See: olfactory tract. Synonym: nervi olfactorii, fila olfactoria, first cranial nerve, nerve of smell, olfactory fila. (05 Mar 2000) |
|---|---|
| fourth cranial nerve | <anatomy, nerve> The trochlear nerve controls an extraocular muscle. Lesions of this nerve will result in rotation of the eyeball upward and outward (and double vision). Synonym: cranial nerve IV. (27 Sep 1997) |