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Cranial Nerves - Anatomy & Physiology (view source)
Revision as of 08:42, 11 August 2011
, 08:42, 11 August 2011→Introduction
[[Image:brainstemcranialnervespyramids.jpg|thumb|right|150px|The brainstem, cranial nerves and pyramids. © BioMed Archive.]]
[[Image:brainstemcranialnervespyramids.jpg|thumb|right|150px|The brainstem, cranial nerves and pyramids. © BioMed Archive.]]
==Introduction==
==Introduction==
Cranial nerves are those nerves which arise from the brain and brain stem rather than the spinal cord. Nerves arising from the spinal cord are the [[PNS Structure - Anatomy & Physiology|peripheral nerves]]. There are 12 pairs of cranial nerves and these pairs of nerves passage through foramina in the skull, either individually or in groups.
Cranial nerves are those nerves which arise from the brain and brain stem rather than the spinal cord. Nerves arising from the spinal cord are the [[PNS Structure - Anatomy & Physiology|peripheral nerves]]. There are 12 pairs of cranial nerves and these pairs of nerves passage through foramina in the skull, either individually or in groups. Cranial nerves are traditionally referred to by Roman numerals and these numerals begin cranially and run caudally.
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The most cranial nerve is the '''Olfactory nerve (I)''' which runs from the nasal cavity through to the olfactory bulb. The next most cranial is the '''Optic nerve (II)''' which runs from the eyes to the thalamus. Cranial nerves III to XII all exit from the brain stem and in order of most cranial to caudal include the '''Oculomotor nerve (III)''', the '''Trochlear nerve (IV)''', the '''Trigeminal nerve (V)''', the '''Abducens nerve (VI)''', the '''Facial nerve (VII)''', the '''Vestibulocochlear nerve (VIII)''', the '''Glossopharyngeal nerve (IX)''', the '''Vagus nerve (X), the '''Accessory nerve (XI)''' and the '''Hypoglossal nerve (XII)'''.
==Cranial Nerve Groups==
==Cranial Nerve Groups==
There are three main groups of cranial nerves; special senses, innervation of the head muscles and innervation of structures originating from brancial arches. The special senses cranial nerves include the olfactory, ocular and vestibulocochlear. Cranial nerves related to the innervation of the head muscles include the oculomotor, trochlear, abducens and the hypoglossal nerves. Cranial nerves related to innervation of structures originating from branchial arches includes the trigeminal, facial, glossopharyngeal, vagus and accessory nerves.
There are three main groups of cranial nerves; special senses, innervation of the head muscles and innervation of structures originating from brancial arches. The special senses cranial nerves include the olfactory, ocular and vestibulocochlear. Cranial nerves related to the innervation of the head muscles include the oculomotor, trochlear, abducens and the hypoglossal nerves. Cranial nerves related to innervation of structures originating from branchial arches includes the trigeminal, facial, glossopharyngeal, vagus and accessory nerves.