Cranial Nerves PDF

- The CI- C7 spinal nerves exit the vertebral canal superior to their respective cervical vertebrae. The C8 spinal nerve exits inferior to the C7 vertebra. All of the remaining 10 spinal...

- The CI- C7 spinal nerves exit the vertebral canal superior to their respective cervical vertebrae. The C8 spinal nerve exits inferior to the C7 vertebra. All of the remaining 10 spinal nerves segmentally exit the vertebral canal inferior to their respective vertebra. Cranial Nerves Twelve pairs of cranial nerves arise from the brain, and they are identified both by their names and by Roman numerals I to XII. 1 1- The olfactory nerve (CN 1): sensory nerve for the sense of smell. 2- The optic nerve (CN II): sensory nerve for the sense of vision. 3- The oculomotor nerve (CN IIl): motor nerve carries two types of fibers: engine ? Motor fibers innervate most of the extra-ocular muscles. AllMuscles excepi 139U ? Parasympathetic fibers it enables constriction of the pupil (miosis and lens 91 stin, accommodation. it ate Some says Marry money But My big Brother says Big brain mater B ? BOTh 51 ? sensors  GENERAL HUMAN ANATOMY , 69 4. The trochlear nerve (CN IV): motor nerve, innervate the superior oblique muscle, an extra-ocular muscle in the orbit. 5- Trigeminal nerve (CN V): It is a mixed nerve, It is the major sensory nerve of the head and face, and its motor part innervates muscles that move the lower jaw (muscles of mastication). It is divided into 3 divisions: a- Ophthalmic division [V1] (pure sensory) b- Maxillary nerve [V2] (pure sensory) c- Mandibular division [V3] (mixed nerve) 6- Abducent nerve (CN VI): motor nerve innervates one of the extraocular muscles, the lateral rectus muscle. 7- Facial nerve (CN VII): mixed nerve ? Motor fibers: for the muscles of the facial expressions. ? Sensory fibers: carry taste sensation from the anterior two-thirds of the tongue. Parasympathetic fibers: secretory fibers for the submandibular and sublingual salivary glands and the lacrimal gland 8- Vestibulocochlear nerve (CN VIII): sensory nerve. It has two components a- Vestibular part: mediates balance and motion b- Cochlear part: for hearing. 9- Glossopharyngeal nerve (CN IX): mixed nerve. ? Motor fibers: for one muscle of the pharynx (stylopharyngeus). ? Sensory fibers: carry general and taste sensation from the posterior one- third of the tongue and from the pharynx. ? Parasympathetic fibers: secretory fibers for parotid salivary gland. 10- Vagus nerve (CN X): mixed nerve ? Motor fibers: for most of the muscle of the larynx. ? Sensory fibers: carry sensation from the root of the tongue and from the larynx. ? Parasympathetic fibers: supply the smooth muscles and glands of the visceral organs. 11- Accessory nerve (CN XI): motor nerve. It has two parts a- Cranial part: from the medulla oblongata: its fibers join the vagus nerve. b- Spinal part: arise from the cervical spinal nerves (C1-C5). It supplies two muscles in the neck (sternomastoid and trapezius muscles). 12- Hypoglossal nerve (CN XII): motor nerve supplying intrinsic and extrinsic muscles of the tongue (except for the palatoglossus muscle). N.B.: - Pure sensory nerves include olfactory (CN 1), optic (CN Il) and vestibulocochlear (CN VIII) nerves.