The cranial nerve Ⅰ. Olfactory nerve Ⅱ. Optic nerve

The cranial nerve Ⅰ. Olfactory nerve Ⅱ. Optic nerve Ⅲ. Oculomotor nerve Ⅳ. Trochlear nerve Ⅴ. Trigeminal nerve Ⅵ. Abducent nerve Ⅶ. Facial nerve Ⅷ. Vestibulocochlear nerve Ⅸ. Glossopharyngeal nerve Ⅹ. Vagus nerve Ⅺ. Accessory nerve Ⅻ. Hypoglossal nerve

2. The cranial nerves consist of 4 kinds of fibers: • somatic sensory fibers • visceral sensory fibers • somatic motor fibers • visceral motor fibers • 3 types: • Sensory (afferent) nerves: I、Ⅱ、Ⅷ • Motor (efferent) nerves: III、Ⅳ、Ⅵ、Ⅺ、Ⅻ • Mixed nerves: Ⅴ、Ⅶ、Ⅸ、Ⅹ

Ⅱ. The sensory nerves: • Olfactory nerve: • Visceral sensory fibers • Cell bodies are in nasal • Mucosa olfactory region • (on the superior • nasal concha and opposed • part of nasal septum) • Pierces through cribriform • foramina and ends in • olfactory bulb. • Conducts sense of smell.

Ⅱ. The sensory nerves: • 2. Optic nerve • somatic sensory fibers. • The central processes of ganglion cells • of retina converge on optic disc, then • pierce the sclera and form optic nerve. • passes through optic canal into middle • cranial fossa, then joints optic chiasma. • conveys the sense of sight.

III Oculomotor nerve (external squint) Contains special and general visceral motor fibers • Enter orbit through the superior orbital fissure. • The special visceral motor fibers supply the extraocular muscles except for the superior obliquus and lateral rectus • The general visceral motor fibers innervate the ciliary muscle and sphincter pupillae muscles

superior obliquus Oculomotor nerve The general somatic motor fibers diplopia Trochlear n. Abducent n. ciliary muscle sphincter pupillae muscles The general visceral motor fibers

Trochlear nerve(CN IV) • passes into orbit through the superior orbital fissure. • Supplies the superior obliquus

Trochlear nerve: • Emerges from anterior medullary velum • just behind the inferior colliculus—winds • forward around cerebral peduncle— • traverses lateral wall of cavernous sinus • —passes into orbit through the superior • orbital fissure • Supplies the superior oblique muscle.(diplopia)

V. Trigeminal nerve: • It has a motor and a sensory roots.The motor root contains the somatic motor fibers arising from the motor nucleus of trigeminal nerve; Sensory root contains the somatic sensory fibers which are central processes of the neurons located in the trigeminal ganglion.

It’s formed by the peripheral processes of neurons of trigeminal ganglion and few somatic motor fibers. • 3 divisions: —ophthalmic nerve —maxillary nerve —mandibular nerve

Ophthalmic nerve: • a sensory nerve • passes forwards along the lateral • wall of cavernous sinus—separated • into 3 branches—enter the orbit • through the superior orbital fissure : • lacrimal nerve: lacrimal gland • frontal nerve: divided into supratrochlear n. • supraorbital nn. • which distributed to the skin • of forehead and anterior part • of scalp. • nasociliary nerve: eyelid, nasoal sinuses,skin and mucosa of nose.

Maxillary nerve • a sensory nerve. • traverses the lateral wall of cavernous • sinus below the ophthalmic n.— • the foramen rotundum—crosses the • pterygopalatine fossa—enter the orbit • through the inferior orbital fissure • (infraorbital n.)—passes forwards • the infraorbital groove and canal— • appears on the face through infraorbital • foramen(supplies the ala of nose,lower • eyelid and upper lip)

3 branches: • --- zygomatic n.: skin of cheek and temple • --- pterygopalatine n.: • mucosa of nasal cavity, • palatine and pharynx • --- superior alveolar n: • maxillary sinus, upper gum • and teeth.

Mandibular nerve: • a mixed nerve • through the foramen ovale. • 5 branches: • ---muscular branches: mastication. • ---buccal n.: skin and mucosa of cheek • ---lingual n.: mucosa of anterior • 2/3 of tongue • ---inferior alveolar n.: • mandibular foramen—mendibular • canal—mental foramen(mental n.) • * lower teeth and gum, skin and mucosa of lower lip. • ** muscular branch(mylohyoid and anterior belly of digastric • mm.) • ---auriculotemporal n.: • skin of anterior surface of auricle, temporal region, parotid gland.

Abducens nerve(CN VI) • enters the orbit through the superior orbital fissure. • Innervates the lateral rectus

VII。Facial nerve: • contains 3 types of fibers: • --- somatic motor fibers: • arise from the facial nucleus • --- visceral motor fibers: • arise from the superior salivatory • nucleus. • --- visceral sensory fibers: • arise from the geniculate ganglion • and terminate in the nucleus of solitary tract. • Emerges from the pontomedullary groove just medially to the • vestibulocochlear n.

Passes into the internal acoustic meatus through the internal • acoustic pore—enter the facial canal—turns sharply backwards • and downwards—emerges through the stylomastoid foramen— • runs forward into the parotid gland—gives off 5 brabches.

Branches outside the • facial canal: • --- temporal branch • --- zygomatic branches • --- buccal branches • --- mandibular branch • --- cervical branch • (contain the somatic motor fibers – • mimetic muscles and platysma)

branches within the facial canal: • --- greater petrosal n.: • * formed by visceral motor fibers • (parasympathetic preganglionic • fibers) • * make relay in pterygopalatine • ganglion, postganglionic fibers • supply the lacrimal gland and • glands of nose and palate

branches within the facial canal: • --- chorda tympanic: • Arises from facial n. about 6mm • above the stylomastoid foramen • —enter the tympanic cavity— • pierces anteroinferior wall to • join the lingual n. • * The visceral sensory fibers • (mucous memberane of ant. 2/3 • of tongue and responsible for taste) • * The visceral motor fibers pass into the submandibular ganglion • and make relay, the postganglionic fibers supply the • submandibular and sublingual glands.

VIII. Vestibulocochlear nerve: • somatic sensory fibers • consists of cochlear and vestibular • nerves. • Cochlear nerve is formed by • central processes of bipolar cells of • cochlear ganglion in the central • modiolus of cochlea • Vestibular nerve is formed by • central processes of cells of • vestibular ganglion.

passes into brain stem through internal acoustic meatus. • Conducts sense of hearing and balance.

IX. Glossopharyngeal nerve: • contains 4 types of fibers • --- somatic motor fibers: arise from the nucleus ambiguus. • --- visceral motor fibers:arise from the inferior salivatory nucleus. • --- somatic sensory fibers: arise from the superior ganglion and • terminate in the spinal nucleus of trigeminal nerve. • --- visceral sensory fibers: arise from the inferior ganglion and • terminate in the nucleus of solitary tract. • leaves the skull through the jugular foramen—passes forwards • between the internal carotid artery and internal jugular vein— • passes along the stylopharyngeus — enters the pharynx.

main branches: • --- carotid sinus branch • (to the carotid glomus • and carotid sinus) • --- lingual branch • (to the vallate papillae • & mucous membrane • of the posterior 1/3 of • the tongue) • --- pharyngeal branches • (to the mucousmembrane of • pharynx and • stylopharyngeus)

--- tympanic nerve: * arises from the inferior ganglion of the nerve---ascends to the tympanic cavity to forms the typanic plexus---lesser petrosal n. * The lesser petrosal n. joints the otic ganglion to make rely, postganglionic fibers joint the auriculotemporal n. and to the parotid gland.

X. Vagus n. • contains 4 kinds of fibers • ---somatic motor fibers arising from the nucleus ambiguus. • ---visceral motor fibers arising from the dorsal nucleus of vagus n. • ---somatic sensory fibers arising from the superior ganglion of • vagus n. and stop to the spinal nucleus of trigeminal n. • ---visceral sensory fibers arising from the inferior ganglion of the n. • and stop to the nucleus of solitary tract. • It is attached to medulla oblongata.

It leaves the skull through the • jugular foramen—passes down • in the carotid sheath behind the • internal jugular v. and internal • carotid a.—enters the thorax • between subclavian a. and v. • (crosses the aortic arch on the • left)—through the superior • mediastinum behind the root of • long—to esophagus and forms • the esophagus plexus —ant. and • post. trunks—enter abdominal • cavity through the esophageal • opening of diaphragm—divided into terminal branches.

Main branches: • — superior laryngeal n. • * internal laryngeal n.(mucous • membrane of larynx above • the level of vocal folds) • * external laryngeal n.(supplies • the cricothyroid m.) • — cervical cardiac branches • — pharyngeal branch

Main branches: • — recurrent laryngeal nerve(winds the subclavian a. or the aortic • arch—ascends in groove between the trachea and esophagus— • enters larynx): mucous membrane of the larynx below the level • of vocal folds and rest m. of larynx.

Main branches: • — bronchial branches • — esophageal branches • — anterior and posterior • gastric branches(stomach) • — hepatic branches • — celiac branches

XI. Accessory nerve • Contains somatic motor fibers arising • from the accessory nucleus(spinal root) • and lower part of nucleus ambiguus • (cranial root). • Emerges from the posterolateral sulcus • of medulla oblongata—through the • jugular foramen—descends between • the internal carotid artery and internal • jugular vein—passes back and • downwards to strnocleidomustoid • muscle

XII. Hypoglossal nerve: • Emerges from the anterolateral sulcus (between the olive and • pyramid) of medulla oblongat • —through the hypoglossal canal • —descends between theinternal • carotid artery and internal • jugular vein—passes forwards • over the internal and external • arteries at the level of the angle • of mandible— enters the tongue. • Supplies the intrinsic and • extrinsic muscles of tongue

The cranial nerve Ⅰ. Olfactory nerve Ⅱ. Optic nerve