Cranial Nerves (1,5,7,8,9,10,11 and 12) Slides not included 9th and 10th Cranial 11th and 12th Cranial 8th Cranial Nerve 5th and 7th Cranial 1st Cranial Nerve Nerves Nerves Nerves (3,7,11,12,13,21,23,24) - (10,16) (12,23) Slides included: (14 to 17) *Slides that are not included mostly are slides of summaries or pictures.
Nouf Alabdulkarim. Med 435 Olfactory Nerve [The 1st Cranial Nerve] Special Sensory Olfactory pathway 1st order neuron Receptors Axons of 1st order Neurons Olfactory receptors are specialized, ciliated nerve cells The axons of these bipolar cells 12 -20 fibers form the that lie in the olfactory epithelium. true olfactory nerve fibers.
Which passes through the cribriform plate of ethmoid → They join the olfactory bulb Preliminary processing of olfactory information It is within the olfactory bulb, which contains interneurones and large Mitral cells; axons from the latter leave the bulb to form the olfactory tract. nd 2 order neuron • It is formed by the Mitral cells of olfactory bulb. • The axons of these cells form the olfactory tract. • Each tract divides into 2 roots at the anterior perforated substance: Lateral root Medial root Carries olfactory fibers to end in cortex of the Uncus & • crosses midline through anterior commissure adjacent part of Hippocampal gyrus (center of smell). and joins the uncrossed lateral root of opposite side. • It connects olfactory centers of 2 cerebral hemispheres. • So each olfactory center receives smell sensation from both halves of nasal cavity. NB. Olfactory pathway is the only sensory pathway which reaches the cerebral cortex without passing through the Thalamus .
Trigeminal Nerve [The 5th Cranial Nerve] Mixed Nuclei Trigeminal Branches Ganglion The 5th nerve emerges from the middle of the ventral surface of the pons by 2 roots (Large Lateral sensory root & small medial motor root). Divides into 3 divisions (dendrites of trigeminal ganglion): Principal 1. Ophthalmic Mesenceph (main) Spinal (Pure Sensory) 2. Maxillary Motor nucleus 3. Mandibular alic nucleus sensory nucleus Site: Axons of cells of motor (Pure Sensory) (Mixed) nucleus -Occupies a nucleus join only the Supplies: depression in mandibular division. the middle 1. Upper 2. Face: Motor Sensory cranial fossa. teeth, gums (zygomaticofa Branche 3. Branches: -Importance: & maxillary cial & s: 2. Nasocilia Contains cell 1. air sinus: infraorbital Lacrimal: ry: (midbrain (pons): (pons, (pons): bodies: 1. Frontal: (posterior, nerves). 1. Lingual: supplies supplies &pons): receives medulla & supplies: Whose supplies middle & receives General dendrites carry skin of skin of anterior sensations from receives touch fibers upper 2-3 -Four Muscles skin of superior anterior 2/3 the propriocepti from face & cervical of mastication sensations from face & face, to 8 face & alveolar of tongue. ve fibers scalp segments of (temporalis, the face. lacrimal nasal muscles scalp. nerves). 2. Inferior from spinal masseter, 2. Whose axons gland. cavity & alveolar: (4 muscles of cord): medial & form the eyeball. supplies Lower muscles mastication. receives lateral sensory root of teeth, gums & of pain & pterygoid). trigeminal face. masticat 3. Buccal: ion & temperatur -Other four nerve. supplies Face other 4 e sensations muscles (cheek on upper muscles) from face & (Anterior belly They pass through superior jaw) . 4. scalp. of digastric, orbital fissure to the orbit mylohyoid, Auriculotemporal: tensor palati & supplies auricle, temple, parotid gland & TMJ. Facial Nerve [The 7th Cranial Nerve] Mixed Nuclei Course Branches Nerve Lesions tensor Special General Special tympani). In facial canal: visceral visceral Damage of the visceral 1.Greater petrosal 3.Nerve to efferent: efferent: 2.Chorda tympani facial nerve results afferent: nerve stapedius motor nucleus superior in paralysis of (nucleus carries: of facial salivatory muscles of facial solitarius): a) preganglionic expressions: nerve: nucleus carries parasympathetic control the sends Facial (Bell’s) supplies: preganglionic fibers to amplitude of preganglionic palsy; lower motor muscles of -Emerges from the cerebellopontine parasympathetic submandibular & sound waves parasympathet neuron lesion face, posterior fibers to lacrimal, sublingual from the external ic secretory angle by 2 roots: nasal & palatine glands. environment to (whole face receives taste belly of fibers to 1. Medial motor root: contains motor glands. b) taste fibers the inner ear. affected) from the digastric, sublingual, fibers. from anterior 2/3 anterior 2/3 stylohyoid, submandibula 2. Lateral root (nervous of tongue. • NB. In upper of tongue platysma, r, lacrimal, intermedius): contains Geniculate ganglion: contains cell bodies of neurones; its motor neuron stapedius, and nasal & fibres carrying taste sensations from anterior 2/3 of tongue; lesion (upper face occipitofrontal parasympathetic & taste fibers. palatine -Passes through internal auditory ending in solitary nucleus in M.O. is intact). is. glands. meatus to inner ear where it runs in Lies in internal acoustic meatus. Just as it emerges from the stylomastoid -Face is distorted: Fibers facial canal. - Drooping of foramen it gives: Then emerges from the stylomastoid lower eyelid, 1.Posterior auricular 2.Muscular branches Special Special General foramen & enters the parotid gland - Sagging of to occipitofrontalis visceral visceral visceral where it ends. to posterior belly of mouth angle, muscle. afferent efferent efferent digastric & stylohyoid. - Dribbling of saliva, supplying - Loss of facial parasympathet carrying supplying expressions, ic secretory Inside parotid gland: taste muscles - Loss of chewing, fibers to gives 5 terminal motor branches: Temporal, sensation developed - Loss of blowing, submandibula from from the 2nd Zygomatic, Buccal, Mandibular & Cervical - Loss of sucking, r, sublingual, anterior 2/3 pharyngeal To the muscles of the face. - Unable to show lacrimal, nasal of the tongue. arch. teeth or close the & palatine eye on that side. glands
Vestibulo-Cochlear [The 8th Cranial Nerve] Special sensory Vestibular Nerve Cochlear Nerve Vestibular & cochlear parts leave the ventral surface of brain stem through the ponto-medullary sulcus ‘at crebello-pontine angle’ (lateral to facial nerve), run laterally in posterior cranial fossa and enter the internal acoustic meatus along with 7th nerve. Vestibular nuclei belong to special somatic afferent column in brain stem. Cochlear nuclei belong to special somatic afferent column in brain stem. Medial Vestibulospina Vestibular Auditory Pathway Other Functions Longitudinal Afferent Efferent l Tracts Cortex Afferent *Check the picture in the slides it Fasciculus helps. of some nuclei The cell bodies Function: Extends through •Vestibulospinal The cell bodies From the cochlear nuclei, 2nd order • Superior olivary (1st order 1. control of out the brain fibers influence (1st order neurons) neurons, fibers ascend into the pons, nucleus sends olivocochlear neurons) are posture stem and formed the activity of are located in the where: fibers to end in organ of located in the 2. maintenance of of both spinal motor spiral ganglion 1- Most fibers cross the midline in Corti through the vestibular equilibrium descending & neurons trapezoid body and terminate in the within the cochlea vestibulocochlear nerve. ganglion within 3. co-ordination ascending fibers • concerned nucleus of trapezoid body or in the (organ of Corti in These fibers are inhibitory in the internal of head Projects with the Located in contralateral superior olivary nucleus. inner ear). function and serve to auditory meatus. 4. eye bilaterally control of the lower 2- Some fibers run ipsilaterally and 1-The Peripheral modulate transmission of 1-The movements • Has two body posture part of terminate in the superior olivary nucleus processes: make • From the superior olivary nuclei, sound to the cochlear nerve. Peripheral 5. the conscious components: and balance postcentral dendritic contact ascending fibers comprise the lateral • Superior olivary processes: awareness of 1-The ascending • Two tracts: gyrus with hair cells of lemniscus. containg both crossed (mainly) nucleus & the nucleus of (vestibular nerve vestibular component -Lateral (head the organ of Corti and direct (few) cochlear fibres, which the lateral lemniscus fibers) make stimulation. (vestibulo- arises from area). within the cochlear runs through tegmentum of pons and establish reflex connections dendritic contact They Are: ocular): lateral terminate in the inferior colliculus of the Responsib duct of the inner with motor neurons of with hair cells of 1. To ipsilateral establishes vestibular mdibrain (3rd order neurones). ear. trigeminal and facial motor the membranous flocculonodular connections with (Deiter’s) le for • Some axons within lateral lemniscus 2-The central nuclei mediating contraction labyrinth (inner lobe of the nuclei of the nucleus, conscious terminate in small nucleus of the lateral processes: of tensor tympani and ear). cerebellum Occulomotor, descends awareness lemniscus • The inferior colliculi project (cochlear nerve to medial geniculate nuclei (4th order stapedius muscles as They 2- The central (vestibulocerebell Trochlear & ipsilaterally of fibers) terminate in neurones) of thalamus reduce the amount of sound processes: ar tract) through Abducent nerves -Medial is the vestibular the dorsal and • The axons originating from the medial that gets into the inner ear (form the inferior (motor nuclei for descending sensation. ventral cochlear geniculate nucleus (auditory radiation) in response to loud noise vestibular nerve): cerebellar extraoccular part of the nuclei (2nd order pass through sublenticular part of the • Inferior colliculi establish A. Mostly end up peduncle muscles) for medial internal capsule to the primary auditory neurons), which lie reflex connections with in the lateral, 2. Bilaterally to coordination of longitudinal cortex (Brodmann’s areas 41, 42) located close to the inferior motor neurons in the medial, inferior ventral posterior head & eye fasciculus, in the dorsal surface of the superior cerebellar peduncle cervical spinal segments and superior nucleus of movements. projects temporal gyrus (Heschl’s gyrus) (ICP) in open (tectospinal tract) for the vestibular nuclei thalamus, which 2-The descending bilaterally. • The region surrounding the primary rostral medulla. auditory cortex is known as the auditory movement of head and neck (2nd order in turn project to component: neurons) of the the cerebral extends into the association cortex or Wernick’s area in response to auditory rostral medulla, cortex. spinal cord as the (Brodmann’s areas 22) stimulation. located beneath 3. Bilaterally to medial • Wernick’s area is related to recognition the lateral part of motor nuclei of vestibulospinal and processing of language by the brain. the floor of 4th cranial nerves tract, for control ventricle. (vestibuloocular the posture. B. Some fibers go tract) through to the cerebellum medial through the longitudinal inferior fasciculus. cerebellar 4. To Motor peduncle neurons of the spinal cord as lateral (ipsilateral) directly & medial vestibulospinal (bilateral) tracts through MLF, for control the posture.
Glossopharyngeal [The 9th Cranial Nerve] Mixed Superficial Component of Fibers & Deep Origin Ganglia & Branches Nerve Lesions Course SVE GVE attachment SVA fibers GVA fibers Communications fibers fibers 1. Tympanic: relays in the otic ganglion 1. It Passes forwards 1. It arises from and gives between Internal the ventral secretomotor jugular vein and arise aspect of the from the It has two ganglia: to the parotid External carotid visceral medulla by a cells of 1. Superior ganglion: gland artery. sensation linear series of inferior Small, with no 2. Nerve to It produces: arise from 2. Lies Deep to Styloid ganglion, small rootlets, from mucosa branches. Stylopharynge • Difficulty of process. their in groove inferior of It is connected to the us muscle. swallowing; central 3. Passes between salivatory posterior between olive originate processes Superior Cervical 3. Pharyngeal: to Impairment of external and nucleus third of and inferior from terminate sympathetic ganglion. the mucosa of taste and internal carotid (ISN), tongue, nucleus in cerebellar relay in pharynx, 2. Inferior ganglion: pharynx. sensation over the arteries at the ambiguus nucleus peduncle. otic auditory Large and carries 4. Tonsillar. posterior one- posterior border of (NA), and of solitary 2. It leaves the ganglion, tube and Lingual: supply tract general sensations 5. third of the Stylopharyngeus the tympanic cranial cavity stylophar (NST), the from pharynx, soft carries tongue, palate and then lateral to it. postgangl cavity, by passing yngeusm periphera palate and tonsil. sensory pharynx. ionic carotid 4. It reaches the uscle. l through the fibers sinus, end It is connected to branches, • Absent gag pharynx by passing processes jugular supply in Auricular Branch of general and reflex. Dysfunction supply between middle parotid nucleus foramen in the taste Vagus. special (taste) of the parotid and inferior gland. of solitary company with: buds on The Trunk of the nerve is from the gland. constrictors, deep tract posterior a. the Vagus b. (NST). connected to the Facial posterior third to Hyoglossus, third of Acessory nerve at the stylomastoid of the tongue. where it breaks tongue. nerves foramen. - Sensory branches into terminal c. the Internal from the carotid sinus branches. jugular vein. and body
(pressoreceptors and chemoreceptors).
th Vagus [The 10 Cranial Nerve] Mixed Component of Fibers & Deep Nerve Superficial Ganglia & Branches Course Origin Lesions attachment SVE GVE SVA GVA Communications fibers fibers fibers fibers 1. The vagus runs • Meningeal: to the dura 1. Superior ganglion down the neck on • Auricular nerve: to the external (in the jugular the prevertebral acoustic meatus and tympanic foramen) with: membrane. 1. Its rootlets exit muscles and • Inferior • Pharyngeal: it enters the wall of the from medulla fascia. originate Vagus nerve pharynx. from ganglion of lesions between olive 2. The internal It supplies the mucous membrane of Dorsal glossopharyngeal produce: and inferior jugular vein lies the pharynx, superior and middle Nucleus sensation nerve, constictor muscles, and all the cerebellar behind it, and the of Vagus from carry • Superior muscles of the palate except the -palatal and peduncle. internal and synapses auricle, impulse tensor palati. pharyngeal originate in external from cervical 2. Leaves the skull common carotid and laryngeal from parasym acoustic viscera in sympathetic • To carotid body. through jugular arteries are in paralysis. Nucleus pathetic meatus neck, ganglion • Superior Laryngeal: It divides into: foramen. front of it, all the Ambiguu ganglia, and thoracic • Facial nerve. (1) Internal Laryngeal: It provides 3. It occupies the way down to the -Abnormalities s, to short cerebral and 2. Inferior ganglion sensation to the hypopharynx, the posterior aspect superior thoracic muscles postgangl dura abdomin epiglottis, and the part of the larynx of esophageal (just below the of the carotid aperture. of ionic mater, to al cavities that lies above the vocal folds. • (2) motility, jugular foramen) sheath between -It lies on the pharynx fibers Spinal to External Laryngeal: gastric acid and innervate Tract & Nucleus with: supplies the cricothyroid muscle. secretion, the internal prevertebral muscles larynx. cardiac Nucleus of • Cranial part of • Recurrent Laryngeal: gallbladder jugular vein and fascia. muscle, of Solitary -it goes round the subclavian artery emptying, and smooth Trigemin Tract. accessory nerve, laterally and the -Enters thorax through on the right, and round the arch of muscles al. • Hypoglossal heart rate; and internal and its inlet: the aorta on the left. and other nerve, -It runs upwards and medially common carotid A. Right Vagus glands of autonomic • Superior alongside the trachea, and passes arteries medially. descends in front of viscera. dysfunction. cervical behind the lower pole of the thyroid jugular foramen the subclavian artery. sympathetic gland. B. Left Vagus descends ganglion. -The recurrent laryngeal nerve gives between the left motor supply to all the muscles of the • 1st cervical common carotid and larynx, except the cricothyroid. It also nerve. subclavian arteries. provides sensation to the larynx below the vocal folds.
Accessory [The 11th Cranial Nerve] Motor CorticoNuclear fibers Injury of the Spinal Manifestations of Function Cranial Part Spinal Part Nucleus Spinal Root Injury
Ambiguus Nucleus
-Carries fibers that - Arises from motor originate in the caudal part neurones in ventral horn of -It produces atrophy of nucleus ambiguous the spinal gray matter at Causes: and weakness of -Foramen of exit from skull: levels C1-C5 (spinal -Because of the trapezius. Jugular foramen nucleus) -Unilateral paralysis of 1.Emerges from lateral -Foramen of exit from skull: relatively superficial position of the nerve in trapezius is evident by: aspect of the medulla as a Jugular foramen. 1. Movements linear series of rootlets -The axons leave the cord Receive the posterior triangle, it 1. inability to elevate & caudal to rootlets of the via series of rootlets, of the soft may be damaged by retract the shoulder vagus nerve. emerge laterally midway bilateral palate, penetrating trauma as 2.difficulty in elevating 1 2.At the side of medulla it between the dorsal and corticonuclear larynx, stab wounds . the arm joins the spinal root briefly ventral roots of the spinal pharynx. -It is considered the 3.Winging of scapula 3.It separates once again as nerves. fibers (from most commonly -Dropping of the 2. Controls the the nerve leaves the cranial -Courses rostrally and enter both cerebral iatrgenically shoulder is an obvious cavity through the Jugular the cranial cavity through movements (Induced unintentionally in a pati sign of injury of the foramen. the foramen magnum, and hemispheres). of neck. ent by a physician.) injured nerve. 4.At the level of jugular joins the cranial root nerve as during removal -The lesion also causes: foramen these fibers join briefly. of malignant lymph the valgus nerve and -Separates once again as difficulty in swallowing nodes in the posterior distribute with it to: - the nerve leaves the cranial and speech. muscles of the soft plate cavity through the Jugular triangle. -Inability to turn the -esophagus foramen. head. -pharynx Supplies: the sternomastoid -larynx and trapezius muscles.
Hypoglossal [The 12th Cranial Nerve] Motor
Manifestations of Lesion of CorticoNuclear Course Function Origin & Exit the nerve (LMN)
-The nerve courses 1.Loss of tongue downward with cervical -The hypoglossal nucleus 1. Supplies motor movements neurovascular bundle: receives corticonuclear innervation to all of the 2.Difficulty in chewing and -Origin: Hypoglossal nucleus of (internal carotid artery, fibers from both cerebral muscles of the tongue Except speech the medulla (in the floor of 4th internal Jugular vein, vagus hemispheres. the palatoglossus (which is 3.The tongue paralyses, ventricle) nerve) EXCEPT the region that supplied by the vagus nerve). atrophies, becomes - The fibers emerge from the -Then curves forward behind anterior surface of the medulla supplies genioglossus It Controls the movements shrunken and furrowed on mandible to supply the oblongata through the sulcus muscle (receives and shape of the tongue the affected side (LMN tongue. between the pyramid and the contralateral supply only) during speech and paralysis). -During its initial course, it olive. -Also receives afferent swallowing 4.On protrusion, tongue carries C1 fibers which leave -Foramen of exit from skull: fibers from nucleus 2. Carries proprioceptive deviates to the affected side in a branch to take part in Hypoglossal canal. solitarius and trigeminal afferents from the tongue -If both nerves are the formation of ansa sensory nucleus. muscles. damaged, person can’t cervicalis (a loop of nerves protrude tongue. supplying neck muscles).