Cranial Nerves VII-XII PDF

Cranial nerves VII-XII Class Year 2, Semester 1 Lecturer DR. VIJAYALAKSHMI S B Department of Anatomy Email id: [email protected] Date 30-11-2023 1  Learning Outcomes 1. Describe cranial nerves V...

Cranial nerves VII-XII Class Year 2, Semester 1 Lecturer DR. VIJAYALAKSHMI S B Department of Anatomy Email id: [email protected] Date 30-11-2023 1  Learning Outcomes 1. Describe cranial nerves VII-XII, their nuclei, components and courses 2. Describe foramina, relations and functions of the cranial nerves VII-XII 3. Discuss the effects of lesions to the cranial nerves VII-XII 4. Outline testing the cranial nerves VII-XII 5. Describe the layout of the cervical sympathetic trunk and its cranial branches 6. Define nuclei and pathways of the cranial parasympathetics 7. Describe cranial nerves III, VII, IX and X 8. Discuss lesions of the autonomic system in the head and neck  Cranial nerves Twelve pairs: The first two, i.e. Olfactory & Optic are outgrowths from the forebrain and not actually part of the PNS, but are counted as cranial nerves  Facial – (VII) Branchiomotor - 2nd arch Facial expression Stylohyoid Post belly of digastric Motor Stapedius root Parasympathetic - Secretomotor Lacrimal gland (Lacrimal nucleus) Intermediate Submandibular - Sublingual nerve (Superior salivatory nucleus) Minor salivary glands Somatic sensory - Ear Visceral sensory Taste (hard palate & anterior tongue) (Nucleus tractus solitarius) Facial canal Facial expression and neck muscles Facial nerve and parotid gland Facial nerve – intracranial branches Greater petrosal nerve Nerve to stapedius Chorda tympani  Facial nerve visceral sensory (taste) From anterior 2/3 of the tongue via lingual nerve > chorda tympani From hard palate via greater petrosal nerve Cell bodies in geniculate ganglion > internal acoustic meatus > enters the brain at cerebellopontine angle > N. tractus solitarius  Facial nerve – parasympathetic action Superior salivatory nucleus (lower pons) – secretomotor fibers > into the facial canal >> Greater petrosal > Pterygopalatine ganglion > Lacrimal, palatine, and nasal glands >> Chorda tympani > Joins the lingual nerve > Submandibular ganglion > Sublingual and submandibular glands Post-ganglionic parasympathetic fibres travel along trigeminal branches to reach their destination  Facial nerve- cortical control Motor nucleus in brainstem  Facial nerve- cortical control cortex cortex Motor nucleus in brainstem  Facial palsy cortex Motor nucleus UMN –forehead sparing in brainstem LMN – no forehead sparing  Facial palsy Infra-nuclear: Bell’s palsy Lesion in the internal acoustic meatus – weakness on the ipsilateral side of the face (whole face), loss of taste sensation on anterior 2/3rd of the tongue, decrease in tear production, hyperacusis Lesion at the genu (geniculate ganglion) Lesion distal to the genu (between genu and stylomastoid foramen) - weakness on the ipsilateral side of the face (whole face), loss of taste sensation on anterior 2/3rd of the tongue, hyperacusis and lacrimation normal. Lesion below the stylomastoid foramen – weakness on the ipsilateral side of the face (whole face), taste sensation normal, lacrimation normal. Corneal reflex Vestibulocochlear (VIII)  Vestibulocochlear (VIII) Vestibular - balance Cochlear - hearing Cell bodies in vestibular ganglion Cell bodies in cochlear ganglion Vestibular nuclei Cochlear nuclei Floor of 4th ventricle Floor of 4th ventricle Connections to: Connections to: Vestibulospinal tracts, Medial Medial geniculate body Longitudinal fasciculus (MLF), Inferior colliculi etc. thalamus (VPN) Cerebellum Direct connections to cerebellum also Glossopharyngeal (IX) IX Jugular foramen Superior and inferior ganglion of the glossopharyngeal nerve  Glossopharyngeal (IX) Branchiomotor to 3rd arch Nucleus ambiguous (medulla) >> Stylopharyngeus & pharynx Parasympathetic - Secretomotor Inferior salivatory nucleus (medulla) >> lesser petrosal nerve >> Otic ganglion >> Parotid gland via auriculotemporal nerve Somatic sensory: Ear - tympanic membrane (Cell bodies in superior ganglion >> to trigeminal sensory nuclei) Visceral sensory: Oropharynx, posterior third of the tongue, and carotid body and carotid sinus (Cell bodies in inferior ganglion >> to Nucleus solitarius) Vagus (X) X Jugular foramen Superior and inferior ganglion of the vagus nerve  Vagus (X) Branchiomotor to 4th & 6th arches Nucleus ambiguus Special visceral motor in the neck Swallowing, phonation, palatoglossus Parasympathetic General visceral motor thoracoabdominal Dorsal motor nucleus of the vagus Somatic sensory: Larynx – internal laryngeal nerve Cell bodies in superior ganglion >> to Trigeminal sensory nuclei Visceral sensory Taste at valleculae Various viscera i.e. heart, abdominal viscera Cell bodies at inferior ganglion >> to nucleus solitarius  Vagus injury Normal condition Vagal injury: deviation to the healthy side Accessory (XI) XI Motor Cranial accessory from N. ambiguus Spinal accessory from C1 - C4/5 Ascends through foramen magnum Jugular Emerges from jugular foramen foramen Cranial fibres run to vagus nerve Swallowing & phonation Spinal fibres: SCM + Trapezius Accessory (XI) XI Jugular foramen Accessory (XI) Hypoglossal (XII) XII Somatic motor to tongue Extrinsic Genioglossus- Hyoglossus - Styloglossus Intrinsic Transversal – longitudinal – vertical Hypoglossal Lesion Inside the oral cavity The tongue is deviated to the healthy side When stretched out it deviates towards the side of the lesion ANS in Head and Neck Cervical Sympathetic Sympathetic supply in Head and Neck Ciliary Va Pterygopalatine Vb Vc 1 Submandibular 2 1.Lacrimal 4 2.Nasal, palatine 3 3.Submandibular sublingual Otic 4.Parotid IC EC Superior cervical ganglion Parasympathetic in Head and Neck III VII IX Parasympathetic in Head and Neck Ciliary Pterygopalatine Va III Vb Vc 1 VII Submandibular 2 1.Lacrimal 4 2.Nasal, palatine IX 3 3.Submandibular sublingual Otic 4.Parotid Oculomotor nerve (III) Edinger-Westphal nucleus Midbrain Facial nerve (VII) Superior salivatory nucleus Pons Glossopharyngeal nerve (IX) Inferior salivatory nucleus Medulla  Ciliary Ganglion Somatic Va – Opthalmic Nasociliary branch Superior orbital fissure Parasympathetic Edinger-Westphal CN 3 – Oculomotor Superior orbital fissure Sympathetic (T1) Superior cervical ganglion Via internal carotid plexus  Pterygopalatine Ganglion Somatic Vb – Maxillary Foramen rotundum Parasympathetic & taste CN 7– Facial - Greater petrosal P - Superior salivatory nucleus Taste – Nucleus solitarius Cell bodies in the geniculate ganglion Sympathetic (T1) Superior cervical ganglion Via internal carotid plexus Deep petrosal  Pterygoid Canal GP VII Greater Petrosal (GP) Nerve of the Pterygoid Canal (NPC) Deep Petrosal (DP) DP Pterygopalatine G NPC GP VII DP Pterygopalatine G NPC https://www.brainkart.com/article/Pterygopalatine-Ganglion_14800/  Submandibular Ganglion Somatic Vc – Mandibular Lingual branch Foramen ovale Parasympathetic & taste CN 7 – Facial Chorda tympani Petrotympanic fissure P - Superior salivatory nucleus Taste – Nucleus solitarius Sympathetic (T1) Superior cervical ganglion Via external carotid plexus Facial nerve and gland innervation Pterygopalatine ganglion Submandibular ganglion  Otic Ganglion Somatic Vc – Mandibular Auriculotemporal branch Foramen ovale Parasympathetic P - Inferior salivatory nucleus CN 9 – Glossopharyngeal Jacobson’s (Tympanic) nerve  Tympanic plexus  Lesser petrosal nerve Sympathetic (T1) Superior cervical ganglion Via external carotid plexus Parasympathetic in Head and Neck III VII IX V …. With a little help of a friend….. Parasympathetic and Trigeminal Va Ciliary Vb Vc Pterygopalatine Va III Vb Vc 1 VII Submandibular 2 1.Lacrimal 4 2.Nasal, palatine IX 3 3.Submandibular sublingual Otic 4.Parotid Somatic – CN V Parasympathetic ANS in Head and Neck  Parasympathetic ganglia in Head and Neck - Summary GANGLIA GLANDS/MUSCLE CENTRAL Pre-ganglionic fibers Post-ganglionic S NUCLEUS IN THE travel through… fibers travel BRAIN STEM through… Ciliary Ciliary muscles and Edinger-Westphal Oculomotor nerve Short ciliary nerves ganglion Sphincter pupillae nucleus in the Mid in the eyeball brain Otic ganglion Parotid gland Inferior salivatory Glossopharyngeal Auriculotemporal nucleus in the nerve (Tympanic nerve (Branch V3) Medulla nerve – Tympanic plexus – Lesser petrosal nerve Pterygopalati Lacrimal, Nasal and Lacrimal nucleus in Facial nerve (Greater Zygomatic and ne ganglion palatine glands the Pons petrosal nerve – Lacrimal nerves Nerve to pterygoid (Branches of V2) canal) Submandibul Submandibular and Superior salivatory Facial nerve (Chorda Lingual nerve (V3) ar ganglion Sublingual glands nucleus in the Pons tympani – Lingual to the sublingual nerve) gland Parasympathetic – Summary S. Monkhouse – Cranial Nerves Functional Anatomy- Cambridge  Pancoast‘s Tumor Tumour at lung apex May damage nerves positioned at 1st rib. T1 fibres (brachial plexus) ⚫ small muscles of hand Sympathetic chain ⚫ Interrupts impulses to head Cervicothoracic ganglion (stellate ganglion) ⚫ Ptosis - ipsilateral partial drooping of eyelid ⚫ Miosis - Pupil constriction ⚫ Facial anhidrosis - sweat glands not innervated Horner’s syndrome  References ▪ Snell’s Neuroanatomy ▪ Gray’s Neuroanatomy for Students Practice questions Acknowledgement Prof. Fabio Quondamatteo