Neuronanatomy lesson 12.pdf

NEUROANATOMY Lesson 12: Anatomy of Cranial Nerves Overview of the Peripheral Nervous System (PNS) Overview of the Peripheral Nervous System (PNS) Overview of the Peripheral Nervous System (PNS) Overview of the Peripheral Nervous System (PNS) Overview of the Cranial Nerves The cranial ner...

NEUROANATOMY Lesson 12: Anatomy of Cranial Nerves Overview of the Peripheral Nervous System (PNS) Overview of the Peripheral Nervous System (PNS) Overview of the Peripheral Nervous System (PNS) Overview of the Peripheral Nervous System (PNS) Overview of the Cranial Nerves The cranial nerves are a set of 12 paired nerves that arise directly from the brain. The first two nerves (olfactory and optic) arise from the cerebrum, whereas the remaining ten emerge from the brainstem. The names of the cranial nerves relate to their function and they are numerically identified in roman numerals (I-XII).  Origin of the Cranial Nerves There are twelve cranial nerves in total. The olfactory nerve (CN I) and optic nerve (CN II) originate from the cerebrum. Cranial nerves III to XII arise from the brainstem. Midbrain: the trochlear nerve (IV) comes from the posterior side of the midbrain. It has the longest intracranial length of all the cranial nerves. Midbrain-pontine junction: oculomotor (III). Pons: trigeminal (V). Pontine-medulla junction: abducens, facial, vestibulocochlear (VI-VIII). Medulla oblongata Posterior to the olive: glossopharyngeal, vagus, accessory (IX-XI). Anterior to the olive: hypoglossal (XII). Origin of the Cranial Nerves Superior view of the skull base showing the foramina Tip: Cranial nerves with the number 2 in them (e.g. 2-optic and 12- and which cranial nerves pass through them. hypoglossal) exit through a canal of the same name. They are the only cranial nerves to pass through canals. Modalities Each cranial nerve can be described as being sensory, motor or both.