Cranial Nerve 1x PDF

Cranial Nerves 7-12  Facial nerve (Ⅶ) Components of fibers SVE fibers originate from motor nucleus of facial nerve, and supply facial muscles GVE fibers derived from superior salivatory nucleus and relayed in pterygopalatine ganglion and submandibular ganglion. The postganglionic fibers s...

Cranial Nerves 7-12  Facial nerve (Ⅶ) Components of fibers SVE fibers originate from motor nucleus of facial nerve, and supply facial muscles GVE fibers derived from superior salivatory nucleus and relayed in pterygopalatine ganglion and submandibular ganglion. The postganglionic fibers supply lacrimal, submandibular and sublingual glands. SVA fiber from taste buds of anterior two-thirds of tongue which cell bodies are in the geniculate ganglion of the facial nerve and end by synapsing with cells of nucleus of solitary tract GSA fibers from skin of external ear, external acoustic meatus, tympanic membrane Nuclei of Facial Nerve Main motor nuclei Superior salivatory (-lacrimal)-Parasymphathetic nucleus of glands Nucleus of tractus solitarius - Special Sensory afferent; taste Pontine and spinal trigeminal nuclei-sense from skin 3 4 Cranial Nerve VII: Facial Course: leaves skull through internal acoustic meatus, facial canal makes a bend geniculum,and then enters 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 ganglion, the postganglionic fibers supply submandibular and sublingual glands  Greater petrosal nerve: GVE fibers pass to pterygopalatine ganglion and there relayed through the zygomatic and lacrimal nerves to lacrimal gland, fibers to oral, phyarngeal,nasal mucosa glands, and taste fibers from soft palate Stapedial nerve: to stapedius Branches outside of facial canal Temporal Zygomatic Buccal Marginal mandibular Cervical  Pterygopalatine ganglion: lies in pterygopalatine fossa under maxillary nerve Submandibular ganglion: lies between lingual nerve and submandibular gland Special Sensory (Taste) Ant 2/3 of tongue- chorda tympani&greater petrosal n.- geniculate ganglion - tractus solitarius –ipsilaterally to VP of thalamus-sensory cortex 11 General sensory External ear, ext. acoustic meatus, ext. surface of tympanic membrane-geniculate body TOUCH FIBERS- pontine nucleus of trigeminal nucleus-medial lemniscus-VP of thalamus-sensory cortex PAIN FIBERS -spinal lemniscus-VP & MD of thalamus-sensory cortex &cingulate 14 Motor Motor cortex-corticobulbar fibers (ipsilateral&contralateral)-motor nuclei of CNVII – upper facial muscles (bilateral) & lower facial muscles (contralateral) 18 22 Clinical Info: Facial Nerve (VII) Upper Motor Neuron Disease Why is it hard to only raise one eyebrow? Unilateral paresis of muscles of lower half of face Muscles above bilaterally innervated Bilateral lesion can cause paralysis of upper and lower muscles bilaterally Lower Motor Neuron Disease Injury near pons can cause lower motor neuron disease Unilateral Paralysis of all facial muscles, stapedial muscle and taste in 2/3 of tongue Clinical Examples: Facial Nerve UMN LMN Clinical Info: Facial Nerve (VII) Bell’s Palsy LMN syndrome with sudden onset of paralysis of ipsilateral facial muscles Inflammatory injury, infection or degenerative disease 26 Clinical Examples: Facial Nerve 27 29 VIII: Vestibulocochlear Special Sensory: Auditory/Balance 30 Vestibulocochlear nerve Vestibular ganglion(SSA) Vestibular nuclei Internal acoustic meatus Cochlear ganglion (SSA) Cochlear nuclei Vestibulo-cochlear Nerve (VIII) Special somatic afferent Vestibular Nerve Gives feedback about position of head in space and balance Acoustic Nerve Hearing Clinical Info Tests for equilibrium, vertigo or dizziness, nystagmus and hearing loss 32 Glosso-pharyngeal Nerve (IX) General visceral afferent Mediates general visceral sensation from soft palate, palatal arch, posterior 1/3 of tongue, tympanic cavity Superior glossopharyngeal ganglion, spinal nucleus of trigeminal nerve General visceral efferent Secretion from parotid gland (salivary gland) arise from inferior salivatory nucleus and relayed in otic ganglion Special visceral afferent Taste sensation from posterior 1/3 of tongue arise from the cells of inferior ganglion, the central processes of these cells terminate in nucleus of solitary tract Special visceral efferent Contributes to swallowing through stylopharyngeus and upper pharyngeal constrictor fibers originate from nucleus ambiguus  Main motor nucleus; superior end of nucleus ambiguus Parasympathetic nucleus;inferior salivatory nucleus Special sensory nucleus; nucleus tractus solitarius General sensory; spinal nucleus of trigeminal nerve 34 35 36 37 38 39 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 : GVE fibers via tympanic and lesser petrosal nerves to otic ganglion, with postganglionic fibers via auriculotemporal (Ⅴ3) to parotid gland Carotid sinus branch: innervations to both carotid sinus and glomus Others: tonsillar and stylophayngeal branches Otic ganglion: situated just below foramen ovale Clinical Info: Glosso-pharyngeal (IX) May be evident in dysphagia or loss of taste to posterior 1/3 of tongue Loss of gag reflex Excessive oral secretions Dry mouth Need bilateral damage of nerve to have strong clinical signs 41 Visceral afferent Carotid body&carotid sinus-carotid nerve-inferior glossophyrangeal ganglion-tractus solitarius-reticular formation&hypothalamus 42 Special afferent Taste buds-inf.glossophyarngeal ganglion-tractus solitarius-tractus nucleus solitarius-ipsilateral VP of thalamus-sensory cortex 43 Brachial Motor efferent Motor cortex-corticobulbar tracts-bilateral nucleus ambiguus- CN IX(with X,XI)-stylopharyngeus 44 Parasympathetic Inf. salivatory-CN IX-otic ganglion-auriculotemporal nerve (details will be discussed in ANS) 45 VAGUS NERVE 46 Nuclei of Vagus Nerve Main motor nucleus- nucleus ambiguus Parasympathetic nucleus-dorsal motor nucleus of vagus Special sensory nucleus- nucleus tractus solitarius General sensory nucleus- spinal nucleus of trigeminal nerve 47 48 Vagus Nerve (X) General sensory afferent Sensation from pharynx, larynx, thorax, abdomen Regulates nausea, oxygen intake, lung inflation General visceral efferent Innervates glands, cardiac muscles, trachea, bronchi, esophagus, stomach and intestine Special visceral afferent Mediates taste sensation from posterior pharynx and epiglottis Special visceral efferent Controls muscles of larynx, pharynx, soft palate for phonation, swallowing and resonance 49 Course 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 inlet on right side of trachea Travels downward posterior to right brachiocephalic vein and superior vena cava Passes posterior to right lung root Forms posterior esophageal plexus Forms posterior vagal trunk at esophageal hiatus where it leaves thorax and passes into abdominal cavity, then divides into posterior gastric and celiac branches Left vagus nerve Enter thoracic inlet between left common carotid and left subclavian arteries, posterior to left brachiocephalic vein Crosses aortic arch where left recurrent laryngeal nerve branches off Passes posterior to left lung root Forms anterior esophageal plexus Forms anterior vagal trunk at esophageal hiatus where it leaves thorax and passes into abdominal cavity , then divides into anterior gastric and hepatic branches Branches in neck Superior laryngeal nerve: passes down side of pharynx and given rise to Internal branch, which pierces thyrohyoid membrane to innervates mucous membrane of larynx above fissure of glottis External branch, which innervates cricothyroid Cervical cardiac branches : descending to terminate in cardiac plexus Others: auricular, pharyngeal and meningeal branches  Superior laryngeal nerve Internal branch External branch 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 laryngeal muscles except cricothyroid Bronchial and esophageal branches Branches in abdomen Anterior and posterior gastric branches Run close to lesser curvature and innervate anterior and posterior surfaces of stomach As far as pyloric antrum to fan out into branches in a way like the digits of a crow’s foot to supply pyloric part Hepatic branches: join hepatic plexus and then supply liver and gallbladder Celiac branches: send branches to celiac plexus to be distributed with sympathetic fibers to liver, pancreas, spleen, kidneys, intestine as far as left colic flexure 56  General sensory Posterior meninges, concha, back of ear, ext. acoustic meatus, ext surface of tympanic membrane, pharynx, larynx sup. vagal ganglia-spinal trigeminal tract-medial lemniscus- contralateral VPM of thalamus-sensory cortex Some fibers to contralateral DM- cingulate gyrus 57 58  Visceral Sensory pharynx,larynx,trachea,esophagus, thoracic & abdominal viscera- inferior vagal ganglion-nucleus tractus solitarius- bilateral reticular formation & hypothalamus 59 60 Brachial motor Motor cortex- bilateral corticobulbar fibers-nucleus ambiguus-vagus nerve 61 62 Parasympathetic motor Dorsal motor nucleus of vagus- ganglia medial side of ambiguus-vagus- cardiac ganglia,cardiac plexus 63 64 65 Clinical Info: Vagus Nerve (X) Bilateral lesion of the brainstem can be fatal due to respiratory involvement Unilateral lesion can result in ipsilateral paresis or paralysis of soft palate, pharynx and larynx Pharyngeal Branch Pharynx and soft palate involvement Uvula pulled to unaffected side, bilateral soft palate droops Recurrent Laryngeal Branch Unilateral: Paralysis of vocal folds Bilateral: Inspiratory stridor and aphonia 66 Clinical Info: Vagus Nerve (X) Normal Soft Palate Unilateral Paralysis Bilateral Paralysis 67 Clinical Info: Vagus Nerve (X) Autonomic reflexes reduced Anesthesia of pharynx and larynx and loss of taste Superior Laryngeal Branch Loss of ability to change pitch 68 XI: Spinal Accessory Somatic Motor: Trapezius, Sternocleidomastoid 69  Spinal Accessory Nerve (XI) General visceral efferent Controls head position by controlling trapezius and sternocleidomastoid muscles Clinical Information Affects ability to control head movements Ask patient to rotate head and note control 70 71 72 XII: Hypoglossal Somatic Motor: Tongue 73 Hypoglossal Nerve (XII) General somatic efferent Controls tongue movement Controls extrinsic and intrinsic muscles of tongue except palatoglossal (X) Eating, sucking and chewing reflexes 74 75 76 77 78 Clinical Info: Hypoglossal (XII) LMN unilateral lesion can cause wrinkling and flaccidity of tone with atrophy over time Dysarthria and Dysphagia 79 Clinical Info: Hypoglossal (XII) Unilateral Bilateral Tongue Tongue Paralysis Paralysis 80