It can be argued that there are 10 cranial nerves rather than 12 on th - PDF document

It can be argued that there are 10 cranial nerves rather than 12 on the basis of their origin and constitution. Specically, the olfactory and the optic nerves are different from the other ten cranial nerves in that they both consist of central nervous system cellular components and carry secondary axons rather The numbering of cranial nerves has classically started from I to XII in a cranio-caudal order of nerve root emergence. However this has been recently challenged as new data shows that cranial nerve VI actually emerges at the same level or below the VII and VIII cranial nerves. It is good to know even nerves [1].Cranial nerve anatomy and function is complex, deriving from both the somite and visceral origins of head and neck tissues that are innervated by them. In humans, most head and neck structures derive from ve pharyngeal (or brachial) clefts, arches and pouches. Each arch carries its own cranial nerve that innervates all structures developing from the corresponding arch, cleft and pouch. Muscles that develop from the branchial arches (pharyngeal, laryngeal and facial expression

muscles) are innervated by special visceral efferents (SVE). Muscles that derive from somites (skin, tongue, mucosa) are innervated by general somatic efferents (GSE). Somatic sensation from head, neck, meninges and sinus mucosa reach the brain by general somatic afferents (GSA). Parasympathetic innervation to visceral structures is considered general visceral efferents (GVE). The ve special senses such as olfaction, vision, taste, hearing and balance are considered special afferents (SA). Visceral sensory afferents are sensory information derived from chemoceptors and baroceptors transported to the brain (VS). The following table shows the six different functions that cranial nerves subserve. Cranial nerveNerve nomenclatureOlfactoryTrochlear 168 Cranial nerveNerve nomenclatureTrigeminalGSA (face, oral cavity, FacialGSA (skin, mucosa, external (facial muscles), SA (taste)VestibulocochlearVA(chemo and baroceptors)VagusVA (chemo and baroceptors)Eduardo Corrales C, Mudry A, Jackler RK (2016) Perpetuation of errors in illustrations of cranial nerve anatomy. J Neurosurg 1–7. doi: Cranial Nerves