The Cranial Nerves SHANDONG UNIVERSITY Liu Zhiyu

Names of cranial nerves 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 Ⅹ Vagus nerve Ⅺ Accessory nerve Ⅻ Hypoglossal nerve

Fiber components of cranial n. General somatic afferent(sensory) fibers 一: transmit exteroceptive and proprioceptive impulses from head and face to somatic sensory nuclei of the brain stem; Special somatic afferent (sensory) fibers transmit sensory impulses from special sense organs of vision, equilibrium and hearing to the brain ;

Fiber components of cranial n. General visceral afferent (sensory) fibers transmit interoceptive impulses from the viscera to the visceral sensory nuclei-nucleus of solitery tract; Special visceral afferent (sensory) fibers transmit sensory impulses from special sense organs of smell and taste to the brain;

Fiber components of cranial n. General somatic afferent (motor) fibers : arises from the General somatic motor nuclei and innervate skeletal muscles of eye and tongue. Special visceral afferent (motor) fibers : arises from the Special visceral motor nuclei in the brain and to skeletal muscles derived from gill arches () of embryo：such as the m. of mastication, facial expression and swallowing.

Fiber components of cranial n. General visceral afferent (motor) fibers : arise from the general visceral motor nuclei and relayed in parasympathetic ganglions,e postganglionic fibers supply cardiac muscles，smooth muscles and glands.

Classification of cranial nerves Sensory cranial nerves : contain only sensory fibers Ⅰ. Olfactory nerve Ⅱ. Optic nerve Ⅷ. Vestibulocochlear nerve

Classification of cranial nerves Motor cranial nerves : contain only motor fibers Ⅲ. Oculomotor nerve Ⅳ. Trochlear nerve Ⅵ. Abducent nerve Ⅺ. Accessory nerve Ⅻ. Hypoglossal nerve

Classification of cranial nerves Mixed nerves : contain both sensory and motor fibers Ⅴ. Trigeminal nerve Ⅶ. Facial nerve Ⅸ. Glossopharyngeal nerve Ⅹ. Vagus nerve

Sensory cranial nerves I．Olfactory nerve II. Optic nerve VIII.Vestibulocochlear nerve

Olfactory nerve Olfactory cell → Olfactory nerve → Cribriform foramina → Olfactory bulb Olfactory nerve Function: conduct the smell

Optic nerve Ganglion cell of retina → Optic nerve → Optic canal → optic chiasma→optic tract → lateral geniculate body.

Vestibulocochlear nerve Vestibular nuclei Cochlear nuclei Cochlear ganglion Vestibulocochlear nerve Internal acoustic meatus Vestibular ganglion

Sensory cranial nerves Location of cell body Cranial exit Terminal nuclei Main action Ⅰ Olfactory cells Cribrifom foramina Olfactory bulb Smell Ⅱ Ganglion cells of retina Optic canal Lateral geniculate body Vision Ⅷ Vestibular ganglion of internal ear Internal acoustic meatus Vestibular nuclei Equilibrium Cochlear ganglionof internal ear Cochlear nuclei Hearing

Motor cranial nerves III.Oculomotor nerve trochlear nerve VI. Abducent nerve XI. accessory nerve XII. hypoglossal nerve

Oculomotor nerve Components Nucleus of oculomotor n. Accessory nucleus of oculomotor n. Oculomotor nerve Components General somatic motor（efferent） fiber arises from nucleus occulomotor General visceral motor （efferent） fiber arises from accessory nucleus of Ⅲ supplies : Superior, inferior and medial recti; inferior obliquus; levator palpebrae superioris Sphincter pupillae and ciliary muscle Nucleus of oculomotor n. Accessory nucleus of oculomotor n.

Oculomotor nerve Course: Leave the brain at the interpeduncular fossa; Pass through the lateral wall of cavernous sinus Via superior orbital fissure enter the orbita Oculomotor nerve

The injury of the oculomotor n. may lead to: Droping of the upper eyelid; lateral strabismus ; Dilation of the pupil; The pupillary reflexes disappear Oculamotor paralysis

Trochlear n. arises from the nucleus of trochlear nerve, and pass through the superior orbital fissure to supply the superior obliquus trochlear nerve

abducent n. arises from the nucleus of abducent nerve, and pass through the superior orbital fissure to supply the lateral rectus Abducent nerve

Accessory nerve Cranial root ：arises from nucleus ambiguus; Spinal root arises from the accessory nucleus pass through jugular foramen,and supplies 2 muscles Accessory nerve sternocleidomastoid trapezius

Hypoglossal nerve Hypoglossal canal Nucleus of hypoglossal nerve

Function of Cranial Nerve 12 supplies the intrinsic and extrinsic muscles of the Tongue genioglossus extend the tongue with Contraction So what happens if the CN12 has been damaged ?

Motor cranial nerves N. Nucleus of origin Cranial exit supply Ⅲ Nucleus of oculomotor Superior orbital fissure superior, inferior and medial recti; inferior obliquus; levator palpebrae superioris Accessory nucleus of oculomotor (Parasympathetic ) sphincter pupillea and ciliary muscl Ⅳ Nucleus of trochlear nerve superior obliquus Ⅵ Nucleus of abducent nerve lateral rectus Ⅺ Nucleus of accessory nerve Jugular foramen sternocleidomastoid and trapezius Ⅻ Nucleus of hypoglossal nerve Hypoglossal canal muscles of tongue

Mixed cranial nerves V. Trigeminal nerve VII.Facial nerve IX. Glossopharyngeal nerve X. Vagus nerve

Trigeminal nerve Components of fibers General somatic afferent fibers: transmit facial sensation to sensory nuclei of trigeminal nerve, the fibers have their cell bodies in trigeminal ganglion, Special viceral efferent fibers: originate from motor nucleus of trigeminal nerve, and supply masticatory muscles

Branches Ophthalmic nerve (Ⅴ1, sensory) Branches Frontal nerve : leave the skull through the superior orbital fissure, to enter orbital cavity Branches Frontal nerve : Supratrochlear nerve Supraorbital nerve Lacrimal nerve :→lacrimal gland Nasociliary nerve ; → eyeball

Distribution: Visual organ Part of mucosa of nose Skin above the palpebral fisure and back of nose cerebral dura mater

Maxillary nerve (Ⅴ2, sensory) Leave skull through foramen rotundum Branches Infraorbital nerve Zygomatic nerve Superior alveolar nerve Pterygopalatine nerve

Distribution: Maxillary teeth Mucosa of nose and mouth Skin between the palpebral fissure and oral fissure. cerebral dura mater

Mandibular nerve (Ⅴ3, mixed) Leave the skull through the foramen ovale 卵圆孔 to enter the infratemporal fossa Branches Auriculotemporal nerve Buccal nerve Lingual nerve Inferior alveolar nerve Nerve of masticatory muscles

Distribution: cerebral dura mater; Mandibular teeth and gum; Mucosa of floor of mouth Anterior 2/3 of tongue; Skin of auricular and temporal regions and below the oral fissure; masticatory muscles, mylohyoid, and anterior belly of digastric m.

Facial nerve (Ⅶ) Components of fibers Special visceral efferent fiber: fibers originate from nucleus of facial nerve, and supply facial muscles. General visceral efferent fiber: fibers arise from superior salivatory nucleus and relayed in pterygopalatine ganglion and submandibular ganglion. The postganglionic fibers supply lacrimal, submandibular and sublingual glands.

Facial nerve (Ⅶ) Components of fibers . Special visceral afferent fiber: fiber from taste buds of anterior 2/3 of tongue which cell bodies are in the geniculate ganglion of the facial nerve and end the nucleus of solitary tract. General somatic afferent fiber: fibers distribute the skin of external ear.

Course: leaves skull through internal acoustic meatus, facial canal and stylomastoid foramen, it then enters parotid gland where it divides into five Branches which supply facial Muscles.

Branches within the facial canal Chorda tympani : joins lingual branch of mandibular nerve To taste buds on anterior two-thirds of tongue. Relayed in submandibular ganglionthe postganglionic fibers supply submandibular and sublingual glands Branches within the facial canal

Greater petrosal nerve : fibers pass to pterygopalatine ganglion and the postganglionic fibers through the zygomatic and lacrimal nerves to lacrimal gland Stapedial nerve to stapedius

Branches outside of facial canal Temporal branch Zygomatic branch Buccal branch Marginal mandibular branch Cervical branch

Pterygopalatine ganglion : lies in pterygopalatine fossa under maxillary nerve Submandibular ganglion : lies between lingual nerve and submandibular gland

1. Is this paralysis belong to supranuclear paralysis and infranuclear paralysis ？ 2. How to distinguish the supranuclear paralysis and infranuclear paralysis Injury to the facial nerve

Glossopharyngeal nerve (Ⅸ) Components of fibers Special visceral efferent fiber: originate from nucleus ambiguus, and supply stylopharygeus. general visceral efferent fiber: arise from inferior salivatory nucleus and ralyed in otic ganglion, the postganglionic fibers supply parotid gland. Special visceral afferent fiber: transmit the taste of posterior third of tongue to the nucleus of solitary tract.

Glossopharyngeal nerve (Ⅸ) Components of fibers general visceral afferent fiber: transmit the visceral sensation from mucosa of posterior third of tongue, pharynx, auditory tube and tympanic cavity, carotid sinus and glomus, to the nucleus of solitary tract. general somatic afferent fiber: conduct the sensation from skin of posterior surface of auricle.

Course: leaves the skull via jugular foramen Branches Lingual branches : to taste buds and mucosa of posterior third of tongue Pharyngeal branches : take part in forming the pharyngeal plexus Tympanic nerve : → tympanic cavity and auditory tube, and its general visceral motor fibers via lesser petrosal nerves to end the otic ganglion, the postganglionic fibers via auriculotemporal n.(Ⅴ3) to parotid gland

Branches Carotid sinus branch : →carotid sinus and glomus Others: tonsillar and stylophayngeal branches Otic ganglion : situated just below foramen ovale

Pharyngeal branches Lingual branches Carotid sinus branch

Vagus nerve (Ⅹ) components of fibers general visceral efferent fiber: originate from dorsal nucleus of vagus nerve, synapse in parasympathetic ganglion, short postganglionic fibers innervate cardiac muscles, smooth muscles and glands of viscera Special visceral efferent fiber: originate from the nucleus ambiguus, to muscles of pharynx and larynx

Vagus nerve (Ⅹ) components of fibers general visceral afferent fiber: carry impulse from viscera in neck, thoracic and abdominal cavity to nucleus of solitary tract general somatic afferent fiber: conduct the sensation from auricle, external acoustic meatus and cerebral dura mater to the spinal nucleus of trigeminal n.

Course Right vagus nerve Exits the skull from jugular foramen Descends in the neck in carotid sheath between internal (or common) carotid artery and internal jugular vein Right vagus nerve Enter thoracic cavity on right side of trachea and infront of right subclavian a. and passes posterior to right lung root Forms posterior esophageal plexus and posterior vagal trunk Passes though the esophageal hiatus into abdominal cavity, then divides into posterior gastric 胃后支and celiac branches 腹腔支

Left vagus nerve Enter thoracic cavity between left common carotid and left subclavian arteries, Descends infront of the aortic arch Passes posterior to the root of left lung Forms anterior esophageal plexus and anterior vagal trunk Passes though the esophageal hiatus into abdominal cavity, and divides into anterior gastric and hepatic branches.

Branches in neck Superior laryngeal nerve Internal branch which pierces thyrohyoid membrane to innervates mucous membrane of larynx above fissure of glottis External branch, which innervates cricothyroid Internal branch External branch Cervical cardiac branches descending to terminate in cardiac plexus

Branches in thorax Recurrent laryngeal nerves Right one hooks around right subclavian artery, left one hooks aortic arch Both ascend in tracheo-esophageal groove Nerves enter larynx posterior to cricothyroid joint, the nerve is now called inferior laryngeal nerve Innervations: laryngeal mucosa below fissure of glottis , all laryngeal muscles except cricothyroid Bronchial and esophageal branches

Anterior and posterior gastric branches Branches in abdomen Anterior and posterior gastric branches Run close to lesser curvature and innervate anterior and posterior surfaces of stomach Hepatic branches : supply liver and gallbladder Celiac branches: send branches to celiac plexus whose fibers distribute with sympathetic fibers to liver, pancreas, spleen, kidneys, intestine as far as left colic flexure

Nucleus of oculomotor n. Accessory nucleus of oculomotor n.

Auriculotemporal nerve Inferior alveolar nerve

The nerve distribution of tongue 舌的神经分布 Hypoglossal n. → the musels of tongue; Mandibular n. → anterior 2/3 mucosa of tongue; Facial n. → anterior 2/3 teste buds of tongue; Glossopharygeal n. →the mucosa and teste buds of the root of tongue

? The nerve distribution of the eyeball III →sup. Inferior and medial rectus,inferior obliquus IV→ superior obliquus VI→lateral rectus Optic n. → visual sense; Ophthalmic n. →general sense of eyeball; sympathetic n. →dilator pupillae; parasympathetic n. →sphincter pupillae and ciliary m.