Cranial nerve Dept. of Anatomy Zhou Hong Ying

Cranial nerve Dept. of Anatomy Zhou Hong Ying

Key Points of Learning Name Components Passing through Peripheral distribution Central connection Function

Cranial nerve Ⅰ olfactory Ⅱ optic Ⅲ occulomotor Ⅳ trochlear Ⅴ trigeminal Ⅵ abducens Ⅶ facial Ⅷ vestibulocochlear Ⅸ glossophryngeal Ⅹ vagus Ⅺ accessory Ⅻ hypoglossal

Cranial nerve: connect with brain

Openings and fissures on base of skull for CN

CRANIAL NERVE General somatic motor (GSM) General visceral motor (GVM) Special visceral motor (SVM) General somatic sensory (GSS) Special somatic sensory (SSS) General visceral sensory (GVS) Special visceral sensory (SVS) Every pair of CN has not all of the above components.

CRANIAL NERVE

Pure sensory CN olfactory n. optic n. vestibulocochlear n.

Olfactory nerve CN I Pure sensory (SVS) -- smell Olfactory bulb of telencephalon Leaves cranial cavity through foramina in cribriform plate Distributes to mucosa of superior part of lateral and septal walls of nasal cavity.

Olfactory nerve CN I

pure sensory (SSS)-- sight Connects with optic chiasma of diancephlon. Leaves cranial cavity through optic canal. Distributes to retina of eyeball optic n.(Ⅱ)

optic nerve, chiasma, optic tract

Ⅷ vestibulocochlear conveys impulses from inner ear. sense of position terminates in vestibular N, sense of hearing in cochlear N

Pure sensory (SSS) Internal acoustic meatus internal ear Vestibular nerve is responsible for equilibrium Cochlear nerve is responsible for hearing Vestibulocochlear N.

Pure motor CN oculomotor n. trochlear n. abducens n. accessory n. hypoglossal nerve

oculomotor n. trochlear n. abducens n.

Oculomotor n.(gsm and GVM) Midbrain Superior orbital fissure Superior division--superior rectus & levator palpebrae superioris Inferior division supplies inferior & medial rectus, & inferior oblique. GVM fibers parasympathetic, supply ciliary muscle and sphincter pupillae. Trochlear N Pure motor (GSM) ; midbrain ; Superior orbital fissure ; Superior oblique m Abducens N Pure motor (GSM) ; Pons ; Superior orbital fissure Lateral rectus m

Two roots Pure motor Medulla & spinal cord Jugular foramen Cranial root--joins X Spinal root-- sternocleidomastoid & trapezius accessory n.

(Ⅻ)Hypoglossal n.

(Ⅻ)Hypoglossal nerve Pure motor (GSM) Medulla Hypoglossal canal extrinsic and intrinsic muscles of tongue.

Mixed CN trigeminal n. facial n. glossopharyngeal n. vagus n.

Trigeminal nerve V pons Has three divisions: ophthalmic, maxillary, and mandibular nerve Has both sensory and motor components. It is the main sensory nerve for head and face. Its motor nerve innervates the muscles of mastication, etc.

Three divisions: Ophthalmic Superior orbital fissure into orbital cavity Maxillary-foramen rotundum into pteygopalatine Mandibular foramen ovale

Trigeminal nerve ophthalmic N

Trigeminal nerve ophthalmic N superior orbital fissure Lacrimal nerve to lacrimal gland. Frontal nerve to forehead Nasociliary nerve to eyeball, part of nasal cavity, and skin of dorsum of nose from root to top.

Trigeminal nerve maxillary N foramen rotundum pterygopalatine fossa inferior orbital fissure, sulcus, canal and foramen to part of nasal cavity, maxilla, upper teeth, and skin between eye and mouth

Lingual nerve to anterior 2/3 of tongue Inferior alveolar nerve to mandible, lower teeth, and chin Buccal nerve to cheek Auriculotemporal nerve to parotid gland and temporal region SVM fibers supply muscles of mastication, tensor veli palatini, and tensor tempani, etc. Mandibular n.

tensor tympani M

Anterior belly of digastric M

Sensory fibers of CN V

Ⅶ Facial nerve in the temporal bone and main branches and distribution Mixed (SVM, GVM, SVS) Pons internal acoustic meatus canal of facial nerve stylomastoid foramen parotid gland SVM fibers supply muscles of facial expression & stapedius GVM fibers synapse in pterygo-palatine ganglion to supply lacrimal gland; in submandibular ganglion submandibular & sublingual gland SVS fibers receive taste from anterior 2/3 of tongue

Ⅶ Facial nerve facial n in the internal auditory meatus

facial n in the internal auditory meatus, canal, through the stylomastioid foramen

Ⅶ Facial nerve distributes to expression muscles

Ⅶ Facial nerve distributes to mucous of tongue taste

CN Ⅶ distributes to submandibular gland and sublingual gland through the submadibular ganglion

(Ⅸ) glossopharyngeal n. Mixed; medulla; jugular foramen GS fibers to carotid sinus and body, oropharynx, and posterior 1/3 of tongue SVS fibers receive taste from posterior 1/3 of tongue SVM fibers supply stylopharyngeus GVM fibers synapse in otic ganglion to supply the parotid gland

(Ⅸ)glossopharyngeal n.distributes to pharyngeal muscle, parotid salivary gland

(Ⅸ) distributes to carotid body (chemoreceptors) carotid sinus (baroreceptors )

(Ⅸ)glossopharyngeal n. distributes to tongue general somatic and special taste sensory(posterior third)

(Ⅸ)glossopharyngeal n.

The vagus nerve in the neck, thorax, and abdomen Mixed; medulla; jugular foramen; carotid sheath, on the side of mediastinum, esophgeal plexus, esophgeal hiatus anterior and posterior vagal trunks

Parasympathetic fibers in the vagus nerve Parasympathetic fibers originate from the dorsal motor nucleus of vagus. They are distributed widely throughout the respiratory,gastrointestinal system and cardiovascular. GVM

The afferent fibers of vagus n. 1.receptor for general sensation in tympanic membrane, external autitory meatus, and part of the concha of the external ear. 2. receptor for general viscera sensation are distributed widely throughout the mucous membrane of the respiratory,gastrointestinal system and internal layer of the cardiovascular. 3.chemoreceptors are distributed in aortic bodies and baroreptors in the aortic arch GVS, GSS

motor fibers in the vagus nerve innervates to the muscles of larynx and pharynx through the superior laryngeal nerves and the recurrent nerves SVM

Ophthalmic division Sensory (GSA) Trigeminal Cornea, skin of forehead, scalp, eyelids, and nose; also mucous membrane of paranasal sinuses and nasal cavity Maxillary division Sensory (GSA) Skin of face over maxilla; teeth of upper jaw; mucous membrane of nose, the maxillary sinus, and palate Mandibular division Motor (SVE) Sensory (GSA) Muscles of mastication, mylohyoid, anterior belly of digastric, tensor veli palatini, and tensor tympani Skin of cheek, skin over mandible and side of head, teeth of lower jaw and temporomandibular joint; mucous membrane of mouth and anterior part of tongue

Motor (SVE) Facial Muscles of face and scalp, stapedius muscle, posterior belly of digastric and stylohyoid muscles Sensory (SVA) Secretomotor (GVE) parasympathetic Taste from anterior two-thirds of tongue, from floor of mouth and palate Submandibular and sublingual salivary glands, the lacrimal gland, and glands of nose and palate Motor (SVE) Glossopharyngeal Stylopharyngeus muscle assists swallowing Secretomotor (GVE) parasympathetic Sensory (GVA, SVA, GSA) Parotid salivary gland General sensation and taste from posterior one-third of tongue and pharynx; carotid sinus (baroreceptor); and carotid body (chemoreceptor)

SUMMARIZE Nerves of eye Nerves of tongue nerves of pharynx

Case A 49-year-old man woke up one morning to find the right side of his face paralyzed. When examined by his local medical practitioner, he was found to have complete paralysis of the entire right side of the face. He was also found to have severe hypertension. The patient talked with slightly slurred speech. The physician told the patient that he had suffered a mild stroke, and he was admitted to the hospital. The patient was later seen by a neurologist who disagreed with the diagnosis.

External Features of Brain Stem External structure: superficial markers Internal structure: grey matter, white matter, reticular formation Important section levels

External structures Midbrain Pons Medulla oblongata

Ventral aspect of medulla Anterior median fissure Hypoglossal nerve Pyramid Glossopharyngeal nerve Decussation of pyramid Vagus nerve Olive Accessory nerve Preolivary sulcus & Postolivary sulcus

middle cerebellum peduncle basilar sulcus cranial nerves Ⅴ,Ⅵ,Ⅶ,Ⅷ The ventral surface of pons

Ventral view of midbrain Massive crural cerebri interpeduncular fossa oculomotor nerve Floor of the fossa is called posterior perforated substance due to the many blood vessels perforate the midbrain.

Dorsal surfaces of the pons and medulla rhomboid-shaped fossa Boundary Lateral recess/aperture Median sulcus Aqueduct

Dorsal surfaces of the pons and medulla stria medullaris sulcus limitans medial eminence vestibular area: vestibular nuclei lie beneath the vestibular area facial colliculus : abducens nucleus

Dorsal surfaces of the pons and medulla hypoglossal triangle lie within the medial eminence just inferior to stria medullaris. dorsa vagus motor nucleus lie beneath vagus motor dorsal triangle. gracilis tubercle, cuneate tubercle

dorsa surface of mid brain superior and inferior colliculi/quadrigemina corpora tectum of the midbrain Cranial nerve Ⅳ