Cranial nerves
| Cranial nerves | |
|---|---|
Left View of the human brain from below, showing origins of cranial nerves. Right Juxtaposed skull base with foramina through which many nerves exit the skull. | |
Cranial nerves as they pass through the skull base to the brain | |
| Details | |
| Identifiers | |
| Latin | nervus cranialis (pl: nervi craniales) |
| MeSH | D003391 |
| TA98 | A14.2.01.001 A14.2.00.038 |
| TA2 | 6142, 6178 |
| FMA | 5865 |
| Anatomical terms of neuroanatomy | |
Width2, Width.| Cranial nerves |
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Cranial nerves are nerves that emerge directly from the brain, including the brainstem, in contrast to spinal nerves, which emerge from segments of the spinal cord. They relay information between the brain and various parts of the body, primarily to the head and neck regions and are responsible for special senses of vision, taste, smell, and hearing.
The cranial nerves emerge from the central nervous system above the level of the first vertebra of the vertebral column. Each cranial nerve is paired and is present on both sides.
There are conventionally twelve pairs of cranial nerves, which are described with Roman numerals I–XII. Some considered there to be thirteen pairs of cranial nerves, including the non-paired cranial nerve zero. The numbering of the cranial nerves is based on the order in which they emerge from the brain and brainstem, from front to back.
The terminal nerves (0), olfactory nerves (I) and optic nerves (II) emerge from the cerebrum, and the remaining ten pairs arise from the brainstem, which is the lower part of the brain.
The cranial nerves are considered components of the peripheral nervous system (PNS), although on a structural level the olfactory (I), optic (II), and trigeminal (V) nerves are more accurately considered part of the central nervous system (CNS).