Much of our perception of the outside world is mediated by our twelve cranial neurons. The sensory ganglia of the cranial nerves enable us to see, taste, hear, smell, and feel. They are constructed of elements derived from the neural crest and cranial placodes (see Barlow 2002). The motor ganglia of the cranial nerves are involved with eye, neck, and head movements, as well as feeding, speech, and facial expression (see Guthrie 2007).
The cranial nerves are:
The memorization of the twelve cranial neurons and their functions used to constitute a major portion of one’s neuroanatomy and embryology courses. However, when developmental biology began concentrating on mechanisms (transcription factors, paracrine factors, adhesion molecules, etc.), this anatomical tradition was largely abandoned. As Anne Fausto-Sterling (2003) has written, “Similarly, I eliminated the tradition of asking students to memorize all 12 cranial nerves, assuming that those students who became neurosurgeons would have to return to a careful study of these nerves, but that others could learn important principles of nerve anatomy from a more limited sampling.”
However, they remain critically important to any investigation of vertebrate or medical neurobiology. In order to memorize them, many mnemonics have percolated through generations of medical school classes. These include:
On Old Olympus’ Towering Tops, A Finn And German Viewed Some Hops
Odor Of Orangutans Terrify Tarzan After Forty Voracious Gorillas Viciously Attacked Him
Or, more recently:
Only Owls Observe Them Traveling And Finding Voldemort Guarding Very Secret Horcruxes
Others, including more obscene mnemonics, can be seen at:
Barlow, L. A. 2002. Cranial nerve development: placodal neurons ride the crest. Curr. Biol. 12: R171–173.
Guthrie, S. 2007. Patterning and axon guidance of cranial motor neurons. Nature Rev. Neurosci. 8: 859–871.
Fausto-Sterling, A. and S. F. Gilbert. 2003. Educating for social responsibility: changing the syllabus of developmental biology. Int. J. Dev. Biol. 47: 237–244.