Cranial Nerves Handout PDF

Overview of the Nervous System Nervous System Central Nervous System Peripheral Nervous System (CNS) (PNS) Brain Spinal Cord Everything Else 24 October 2024 Anatomy 200 - Livy 1 Periphera...

Overview of the Nervous System Nervous System Central Nervous System Peripheral Nervous System (CNS) (PNS) Brain Spinal Cord Everything Else 24 October 2024 Anatomy 200 - Livy 1 Peripheral Nervous System Everything Else Cranial Nerves ↳ come off brainstem Spinal Nerves ↳ come off spinal cord Peripheral Ganglia 24 October 2024 Anatomy 200 - Livy 2  Spinal Nerves vs. Cranial Nerves Spinal Nerves - Emerge from the spinal cord Cranial Nerves - Emerge from the area of the brain stem 24 October 2024 Anatomy 200 - Livy 3  Cranial Nerves 12 prs of peripheral nerves (like spinal nerves) Numbered (Roman numerals) from I to XII Essentially run the functions of the head & neck (except CN X) ↳ vagus nerve Some CNs pure motor, some pure sensory, others mixed CNIII A ↳ le : vision , smell , X VII , IX , -> Parasumpathetic Arise from & interact with nuclei (motor, sensory, parasympathetic) in brainstem Cell bodies of sensory neurons live in CN ganglia (like dorsal root ganglia) 24 October 2024 Anatomy 200 - Livy 4 I – Olfactory & don't come right off II – Optic - the brainster I III – Oculomotor IV – Trochlear II V – Trigeminal III VI – Abducens IV VII – Facial V VII VI VIII –Vestibulocochlear VIII (Audiovestibular) IX – Glossopharyngeal IX, X, XI XII X – Vagus XI – Spinal Accessory XII - Hypoglossal ventral CN I - Olfactory Nerve Olfactory Bulb Olfactory Tract Olfactory Nerve ~seperatee (CN I) ~ Cribiform bony Plate skull wh holes Olfactory Epithelium  CN I – Olfactory Nerve Pure sensory – responsible for smell (olfaction) Sensory receptors in roof of nasal cavity – olfactory epithelium Olfactory nerve filaments supply olfactory epithelium Terminate in olfactory bulb à olfactory tract Olfactory tract à 1o olfactory cortex (temporal lobe) Only sensory system to bypass thalamus (sensory relay station) Damage or Disease àhyposmia and/or anosmia ↳ decreased ↳> Mability to smell ability a all to smell 24 October 2024 Anatomy 200 - Livy 7  CN II - Optic Nerve BON Optic Nerve (CN II) retinal ganglia cells Optic Chiasm ' /2 contralateral "2 ipsilateral Optic Tract Lateral Geniculate Nucleus visual # 1 Cortey Optic Radiations ↓ project to 10 visual cortex & 10 Visual coccipital lobe) cortex Calcarine Sulcus  CN II – Optic Nerve Pure sensory – vision Receptors in retina of the eye (several layers) Axons of ganglion cells à Optic Nerve (~ 1 million axons) Optic n à Optic Chiasm à Optic tract à lateral geniculate nucleus (thalamus) à Optic Radiations à 1o Visual Cortex 1o Visual Cortex – medial aspect of occipital lobe on either side of Calcarine Sulcus Visual fields projected onto visual cortex in an inverted and reversed fashion ~ Damage or disease à visual field defects le : blindness h 24 October 2024 Anatomy 200 - Livy 9  CN III - Oculomotor Nerve ↳ MIXED NERVE-somatic motor parasympathetic CNIII - , IV , VI ↳ control eye muscles Levator Palpebrae Oculomotor Nerve (CN III) Superioris m Superior Rectus m Ciliary Ganglion medial Medial Rectus m Inferior Rectus m Inferior Oblique m  CN III – Oculomotor Nerve Somatic motor and Parasympathetic (PS) – mixed nerve Arises from midbrain Motor component upplies medial rectus, superior rectus, inferior rectus, inferior oblique, levator palpebrae superioris (elevator of upper eyelid) Hint to remember: lateralrectus superior oblique a Motor all extra-ocular muscles except LR6SO4 LDCN IV - (LR6SO4 lateral rectus – CN VI, superior oblique – CN IV) Parasympathetic for pupillary constriction & accommodation (ciliary ganglion) Damage or disease à pupillary dilation (unopposed sympathetics) and ophthalmoplegia (eye movements weakened or paralysed) 24 October 2024 Anatomy 200 - Livy 11  CN IV - Trochlear NerveI comes ora brainstem ↳ pure motor nerve (only one) superior Oblique Superior Oblique m muscle Trochlear Nerve (CN IV)  CN IV – Trochlear Nerve Smallest cranial nerve Pure motor Supplies one muscle - superior oblique Only CN to emerge from back of brainstem (midbrain) Isolated damage uncommon 24 October 2024 Anatomy 200 - Livy 13 CN VI - Abducent Nerve & lateral rectus ONLY (pure motor) Abducent Nerve (CN VI) Lateral Rectus m  CN VI – Abducent Nerve Pure motor – supplies one muscle – lateral rectus (abducts the eye, hence the name ‘abducent’) Located at pontomedullary junction Longest intracranial course of all cranial nerves Vulnerable to injury in head trauma or raised intracranial pressure (intracranial hemorrhage, brain tumors) Damage à paralysis of lateral rectus à unopposed action of medial rectus à eye deviates medially à squint (strabismus) Patient complains of double vision (diplopia) Oops... was playing WI RORY 24 October 2024 Anatomy 200 - Livy 15  CN V - Trigeminal Nerve MIXED / 3 branches alensation V1 – Ophthalmic Nerve sensoent Trigeminal Nerve ~ forehead (CN V) ↓ "Sensorytone Trigeminal Ganglion w V3 - Mandibular Nerve V2 – Maxillary Nerve  CN V – Trigeminal Nerve Mixed nerve – sensory and motor (from pons) Has 3 divisions (branches) arising from trigeminal ganglion: - V1 – Ophthalmic nerve à eye (pure sensory) - V2 – Maxillary nerve à cheek (pure sensory) - V3 – Mandibular nerve àmandible (motor + sensory) ↳ Jaw teeth chewing I mixed Disease – Trigeminal Neuralgia (Tic Douloureux) - Mainly V2 and V3 24 October 2024 Anatomy 200 - Livy 17  CN V1 - Ophthalmic Branch Supraorbital Nerves Ophthalmic Nerve (CN V1) Trigeminal Ganglion Ciliary Ganglion  CN V1 – Ophthalmic Nerve Pure sensory Supplies sensation to the frontal and ethmoidal paranasal air sinuses Supplies sensory innervation (general) to nasal cavity Supplies sensation to the upper eyelid, side of the nose, forehead and scalp (supraorbital nerve) 24 October 2024 Anatomy 200 - Livy 19  CN V2 - Maxillary Branch Infraorbital Nerves Maxillary Nerve (CN V2) O infaorkter Trigeminal Ganglion Pterygopalatine Ganglion  CN V2 – Maxillary Nerve Pure sensory Enters floor of orbit through inferior orbital fissure Supplies sensation to: - maxillary air sinus I - nasal cavity - lower eyelid, skin of cheek, upper lip (infraorbital nerve) - maxillary (upper) teeth and gums 24 October 2024 Anatomy 200 - Livy 21  CN V3 - Mandibular Branch d Mandibular Nerve mixed nerve (CN V3) Lingual Nerve Trigeminal Ganglion goest que Otic Ganglion Inferior Alveolar Nerve nerve to lower teeth Mental Nerve Submandibular Ganglion  CN V3 – Mandibular Nerve Mixed nerve – somatic sensory and somatic motor (largest branch) Motor - Supplies muscles of mastication Sensory - lower lip, skin of mandible - mandibular teeth and gums (inferior alveolar nerve) - general sensation to anterior 2/3 of tongue (lingual nerve) - Ends as mental nerve (chin) - Carries proprioceptive information from muscles of mastication to brainstemà force of bite 24 October 2024 Anatomy 200 - Livy 23  CN VII - Facial Nerve ↳ · expressions Pterygopalatine Ganglion Facial Nerve Temporal Greater (CN VII) Branch Petrosal Geniculate Zygomatic Nerve Ganglion Branch Posterior Auricular Stylomastoid Nerve Foramen Chorda Tympani Buccal Submandibular Nerve Branch Ganglion Mandibular Branch Cervical Branch  CN VII – Facial Nerve Mixed nerve – Somatic motor, somatic sensory & ↳ facial parasympathetic expression taste Attached to pons Sensory nerve cell bodies in geniculate ganglion Damage or disease - Patient may lose taste (partly), salivation (partly) or lacrimation in one eye - Bell’s Palsy (hemi-facial paralysis) 24 October 2024 Anatomy 200 - Livy 25  CN VII – Function Motor - muscles of facial expression (5 sets of branches) Y eminative Sensory touch Nr19 o - taste to anterior 2/3 of tongue (via chorda tympani – joins lingual n) Parasympathetic - lacrimal gland for tearing (lacrimation) via pterygopalatine ganglion (V2) - Submandibular & sublingual salivary glands via submandibular ganglion (V3) rest + digest fxn of parasumpathetic 24 October 2024 Anatomy 200 - Livy 26  CN VIII - Vestibulocochlear Nerve Vestibulocochlear Nerve Vestibular Branch ↳ balance + (CN VIII) equilibrium Vestibular Apparatus Cochlear Branch ↳a semicircular canals Organ of Corti  CN VIII – Vestibulocochlear Nerve Pure sensory nerve with 2 components Vestibular - supplies vestibular apparatus (semicircular canals + vestibule) à balance and equilibrium - Disease: Meniere’s syndrome (vertigo, nausea, vomiting) Cochlear - supplies organ of Corti in cochlea à hearing - Bilateral central pathway in brainstem carries this information to the temporal lobe à 1o auditory cortex - Damage or disease à difficulty in localizing sound (deafness rare) 24 October 2024 Anatomy 200 - Livy 28 CN IX - Glossopharyngeal Nerve Glossopharyngeal Nerve (CN IX) Otic Ganglion BIGglandon 1 Parotid Gland Pharygeal Lingual Branch Branches ↑ senses blood pressure Carotid Sinus  CN IX – Glossopharyngeal Nerve Mixed nerve – somatic motor, somatic sensory and parasympathetic backpart Supplies the tongue and the pharynx ↳ touch + taste Attached to medulla Regulates the gag reflex (important) Damage or disease à difficulty in swallowing, loss of gag reflex 24 October 2024 Anatomy 200 - Livy 30  CN IX – Functions Motor to one muscle - stylopharyngeus (elevates pharynx) Sensory (general) - posterior 1/3 tongue, pharynx, carotid sinus + body (for carotid sinus reflex) Sensory (special) - taste to posterior 1/3 of tongue Parasympathetic - supplies parotid gland via otic ganglion 24 October 2024 Anatomy 200 - Livy 31  CN X - Vagus Vagus Nerve Nerve "Wanderer" te ma up on nonso ↑ thorat ↓ abdomen  CN X – Vagus Nerve Mixed nerve – motor, sensory and parasympathetic Attached to medulla Damage or disease à difficulty in speech and swallowing 24 October 2024 Anatomy 200 - Livy 33  CN X – Somatic Motor Functions Motor to muscles of the palate, pharynx and larynx 24 October 2024 Anatomy 200 - Livy 34  CN X – Sensory Functions Sensory to muscles of the palate, pharynx and larynx (stretch) Baroreceptor to hollow organs - stomach and bowel Carries visceral afferents from the organs to the CNS 24 October 2024 Anatomy 200 - Livy 35  CN X – Parasympathetic Activity Essentially functions as the parasympathetic nerve for viscera Parasympathetic motor to smooth muscle in thoracic and abdominal organs up to distal part of transverse colon Regulates heart rate (slows it down) 24 October 2024 Anatomy 200 - Livy 36 Accessory Root Vagus Nerve (CN X) to brany CN XI - Spinal brainstema Spinal Accessory Accessory Nerve out Nerve (CN XI) Accessory Branch Spinal Branch Sternocleidomastoid m Spinal Root Trapezius m & neck/back muscles innervated CNX by  CN XI – Spinal Accessory Nerve Somatic Motor function only Attached to medulla and upper spinal cord Spinal accessory nerve – supplies trapezius and sternocleidomastoid muscles in the neck Damage or disease à weakness when shrugging (elevating) shoulders, turning head to one side against resistance 24 October 2024 Anatomy 200 - Livy 38 CN XII - Hypoglossal Nerve below tongue Hypoglossal Nerve (CN XII)  CN XII – Hypoglossal Nerve Pure motor nerve Attached to medulla Supplies the muscles of the tongue Damage or disease – inability to protrude tongue symmetrically 24 October 2024 Anatomy 200 - Livy 40 Terms of Use Students of the Faculty of Medicine & Dentistry, University of Alberta may display, download, or print slides and images associated with this presentation for personal and educational use only. 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