Cranial Nerves PDF

| SDJF Compilation NEUROANATOMY 2: CRANIAL NERVES Mr. Omar Del Castillo, PTRP CRANIAL NERVES...

| SDJF Compilation NEUROANATOMY 2: CRANIAL NERVES Mr. Omar Del Castillo, PTRP CRANIAL NERVES 6. Abducens [M]  12 pairs ipsilateral affectation =  LR6 – Lateral Rectus is innervated by CN 6 o Abduction of eye; move eye outward ADDITIONAL CRANIAL NERVES  Diplopia (Double Vision) – CN 6 ★ CN 13 Zero Nerve [loc: most rostral] Vertical CN 4 Nerve “N” Nervus Terminalis Horizontal CN 6 [more common form of diplopia] Fxn is somehow related to CN 1 (Olfactory) 7. Facial [B] CN 14 Nerve of “Wrisberg”  Innervates muscles of the face brainster >Cortical Bulbar Tract Nervus Intermedius [loc: bet CN 7 & 8] other of the  Bell’s Palsy ★ = name Part of CN 7 o aka “Prosopoplegia” = has CN affectation ▪ plegia = paralysis facial NAMES ▪ prosopos = face = Responsible for palsy code: O3T2AFAGVAH – Oh Oh Oh To Touch And Feel A Girl’s V* So Hot o DDx: Bell’s vs Stroke legend: S – Sensory, M – Motor, B – Both Bell’s Stroke C/L lower quadrant ANOMIA=Inabilityo 1. Olfactory [S]  Smell Ipsilat. facial paralysis facial paralysis  Anosmia ★ – loss of sense of smell o aka “Refrigeration Palsy” ▪ d/t prolonged exposure to cold Closely related to sense of taste nerve in face is superficial → prolonged ★ Loss of Appetite in TBI – CN 1 exposure to cold can lead to developing 2. Optic [S] neuropraxia (’d nerve conduction  Vision velocity of n.) → bell’s palsy & optic radiation affects the optic tract  Anopsia [op = optic] -> Prosopagnosia ★ MC Visual = ; agnosia  Homonymous Hemianopsia ★ - Agnosia of face · Asteregnosia= o Complication of stroke pts S - Inability to recognize familiar faces o Half of visual field is blind - Complication of stroke / CVA o All objects should be placed on intact side - Affected: Area 18 & 19 o Primarily affects PCA & MCA - Under visual agnosia 3 Types of Agnosia: 3. Oculomotor [M] 1. Visual – MC  Eye movements 2. Tactile ·  Under parasympathetic nervous system 3.  PERRLA (Pupils Equally Round, Reactive to Light & Accommodation) o Light & accommodation reflexes – CN 3 ★ *AVOID prolonged icing on lat. knee - Affected: common peroneal n. → foot drop 4. Trochlear [M] 8. Acoustic / Auditory / Vestibulocochlear [S]  SO4 – Superior Oblique is innervated by CN 4 o action: DOWN & IN  Vestibulo | Cochlear o instruction: look at the tip of your nose o Vestibulo – balance ★ o Cochlear – hearing component [coach lea] ★ Inability to move eyes downwards – CN 4 (SO)  Meniere’s Disease ★ [Meniere’s – Miners inside cave]  Intorsion ★ – inward rotation of eyes by SO o Classic Manifestations: ★ [VTS] ▪ Vertigo 5. Trigeminal [triCHEWminal] [B] ▪ Tinnitus – ringing in the ear  Largest CN [d/t its 3 divisions] ▪ Sense of Fullness in the Ear  Motor – Muscles of mastication (4) [TIME] Benign Paroxysmal Positional Vertigo (BPPV) o Temporalis o Internal Pterygoid CLOSURE - MC form of vertigo seen clinically OF MOUTH o Masseter 9. Glossopharyngeal [B] o External Pterygoid OPENING  Glosso – tongue (responsible for taste in the tongue)  Sensory – 3 divisions:  Pharyngeal – pharynx (innervation of pharyngeal ms) V1 Ophthalmic division ★ Responsible for Corneal Reflex - V2 Maxillary 10. Vagus [B] V3 Mandibular  Longest CN o Responsible for sensation of the face  Also supplies pharyngeal ms  Tic Douloureux (Trigeminal Neuralgia) ★  Parasympathetic; vagal stimulation – ’d HR [mavagal] o Dolor = pain [1 of the 5 Cardinal Signs of Inflammation] CN 9 & 10 are related in fxn. o Idiopathic (unknown & self-limiting) Gag Reflex / Swallowing Reflex o Aggravates pain: eating lunch ★ - Mediated by CNs 9 & 10 (N) / Physiologic Tic – ex: eye twitching, no pain; alleviates c rest o Afferent component – CN 9 [sensory] Pathologic Tic (Tic Douloureux) – when there is pain o Efferent component – CN 10 [motor] - To elicit: put tongue depressor at back of tongue | SDJF Compilation Dysphagia ★ Medulla Oblongata - CN 9 & 10 affected - Responsible for vasomotor center - Impairment in swallowing - Continuous with spinal cord inferiorly - Common in stroke, PD (drooling), CP - Below MO: foramen magnum - Mx: - Part of brainstem most affected in  ICP o Doctor: NGT o Pushes brain downward o PT: chin tuck maneuver to facilitate swallowing o Cushing’s Triad ★ 1. Bradycardia neck dissection 11. Spinal Accessory [M]  Pure motor n. Radical 2. Bradypnea 3. Hypertension  2 portions: o Cranial - Widening of Pulse Pressure (PP) PP Formula: Systolic BP – Diastolic BP o Spinal  Supplies: o SCM – I/L side flexion, C/L rotation For you to be able to localize neurologically (which part/level of pt’s brainstem is affected), it is imperative to know the connections of the CNs o Trapezius – to test upper fibers, shoulder shrug to the 3 parts of the brainstem.  Torticollis ★ o aka “Wry Neck” [2 syllables] ★ Limited neck rot to (R) & side flexion to (L), MB 3 CN 7 affected sensory root Intermedius = 4 · Nervous which ms is tight? (R) SCM is tight in the M O.. ★ Play therapy mx for (R) torticollis: [4 letters] a. to (R) & down 5 b. to (L) & down Pons 6 c. to (R) & up 7 (motor) d. to (L) & up 8 7 (sensory) 12. Hypoglossal [M] 8  Motor fxn for tongue; CN that supplies the ms of the tongue 9 o Palatoglossus MO 10 o Genioglossus 11 o Hyoglossus 12 o Styloglossus  Tongue deviation – always points to the weak side Sample Clinical Correlations & Part of Brainstem Affected: Deviation of tongue PERRLA (CN 3) – Midbrain UMNL involvement Contralateral from lesion site Diplopia (CN 6) – Pons [e.g., CVA] Dysphagia (CN 9 & 10) – Medulla Oblongata LMNL involvement Ipsilateral ★ True about the facial nerve (CN 7), EXCEPT: [cut/damage to CN12] a. Comes via 2 roots, 1 from pons & 1 from MO – TRUE Case: Pt has (R) CVA. If there is CN 12 involvement, what *MO – CN 7 (sensory) – nervus intermedius is the tongue deviation? To (L) Anatomically, CN 8 is in the junction of the pons & MO. Thus, Rationale: (R) CVA = (L) hemiplegia; weak side is (L) somehow it has connections with both parts of brainstem. *Uvula always points to the strong side. When here is CN = Post. circulation : Vertebro Basillar Artery BRAINSTEM STROKE SYNDROMES ★ affectation answer this , Reference: Braddom Tables LOCATION SPECIFIC STRUCTURES BRAINSTEM SIGNIFICANT SYNDROMES AFFECTED AFFECTED CN AFFECTED Almost all CNs are located in the BRAINSTEM, except: Medial Basal Both directly come from the BRAIN 1. Weber 3★ CN 1 Telencephalon ★ FRONTAL LOBE ; under the surface Midbrain ★ = Midbrain Particularly, CN 1 comes from / is connected to the under Tegmentum of 2. Benedict 3★ surface of the cerebrum [telencephalon – cerebrum & b. ganglia] the Midbrain CN 2 Diencephalon ★ [Di = 2] All in - 3. Locked-in Bilateral Basal Pons Not a true peripheral n. but an invaginated fiber tract from the Pons the Pons diencephalon 4. Millard-Gubler Lateral Pons 6&7★ Diencephalon: [SHET] 5. Wallenburg ★ Lateral Medulla Medulla 5 - Subthalamus Notes: [Song: Binibirocha by Andrew E. (NEURO 2 3/14 27:54)] - Hypothalamus (to which CN2 is closely related/connected)  Locked-in Syndrome - Epithalamus - Thalamus o pt cannot move, cannot speak, but vertical eye movements are preserved/spared  Wallenburg Syndrome BRAINSTEM o aka “PICA Syndrome” ★  3 component parts: “Lateral Medullary Syndrome" o Midbrain o artery occluded: Post. Inf. Cerebellar Artery ★ o Pons Bridges the MB & medulla ▪ origin: Vertebral Artery ★ = o Medulla Oblongata | SDJF Compilation Distinguishing Features / Characteristics Unique to EXIT POINTS ★ Wallenburg Syndrome ★ CODE EXIT CN 1. (+) Dysphagia - can only be seen in Wallenburg d/t Cristy Cribriform Plate of Ethmoid ★ 1 involvement of CNs 9 & 10 (Medulla) Often Optic Canal 2 - affected Nucleus Ambiguus 3, 4, 5 & 6 Stays Superior Orbital Fissure (V1 – Ophthalmic) 2. (+) Horner’s Syndrome - 4 Clinical Manifestations: 5 FResh Foramen Rotundum [Ro2ndum] (V2 – Maxillary) o Ptosis 5 o Myosis FOr Foramen Ovale [Oval3] (V3 – Mandibular) o Anhydrosis Ina Internal Auditory/Acoustic Meatus 7, 8 o Enophthalmos Jay2 Jugular Foramen 9, 10, 11 - sympathetic nervous system is affected - affected: descending sympathetic tract Howard Hypoglossal Canal 12 o passes thru MO Clinical Correlation: 3. (+) Crossed Hemianesthesia Jugular Foramen Syndrome - loss of pain & temp on I/L face, but  Affected CNs: 9, 10, 11 loss of pain & temp on C/L body True about the jugular foramen syndrome, EXCEPT: Why is CN 5 involved in Wallenberg Syndrome wherein a. (–) Gag reflex – 9, 10 anatomically it is related to the pons? b. (+) Dysphagia – 9, 10 - That’s why there is loss of pain & temp on c. Weak SCM – 11 I/L face is bc of involvement of CN 5 d. Loss of taste in ant. 2/3 of tongue (responsible for facial sensation) e. NOTA - Specifically involves Spinal Nucleus of CN 5 Rationale: CN 7 is responsible for taste in ant. 2/3 of tongue, *since Wallenburg Syn. affects MO & the nucleus and CN 7 does not pass thru the jugular foramen. If d. is “loss of found in MO is the spinal nucleus taste of post. 1/3 of tongue”, then answer would be e. NOTA *pain & temp is the only affected sensation in since CN 9 is responsible for taste in post. 1/3 of tongue. Wallenberg Syn; light touch & proprio are NOT CN 5 ★ What are the CNs that pass thru the cavernous sinus? - Being the largest CN, it is the only CN that has - CNs 3, 4, 5 & 6 3 sensory nuclei inside the 3 parts of brainstem o V1 – Ophthalmic division o V2 – Maxillary division 3 SENSORY NUCLEI OF CN 5: Cavernous Sinus ★ NUCLEUS LOCATION FXNS [PLP] - A space in the pituitary fossa (sphenoid bone) 1. Mesencephalic Midbrain Facial Proprioception - One of the dural venous sinuses of the brain where 2. Main Sensory Pons Light Touch CNs 3, 4, 5 (V1 & V2), 6 pass thru 3. Spinal Nucleus MO Pain & Temperature Note: [Siegelman]  Midbrain = Mesencephalon GENERAL FUNCTIONS  Main Sensory Nucleus – aka “Chief Sensory Nucleus”  Spinal nucleus – called so bc it has connection to SC Sensory 1, 2, 8  Proprioception – position sense; ability to perceive Mixed 10, 9, 7, 5 the position of body parts in space Motor 3, 4, 6, 11, 12 *Proprioception cranialpart UE Fasciculus Cuneatus CODES: ★ ~only the LE Fasciculus Gracilis 1971 10, 9, 7, 11 Vagal System CNs ★ 1973 10, 9, 7, 3 Parasympathetic (Autonomic) CNs 1975 10, 9, 7, 5 Mixed CNs Vagal System (1971)  CNs that are in the Medulla Oblongata that has connected fxns  Vagal system supplies structures of the throat/pharynx  Cranial part of CN 11 is part of the vagal system ★ o Cranial part joins CN 10 to supply the ms of pharynx CN 11 has 2 parts: spinal & cranial ★ Syringomyelia - Spinal part – supplies SCM & trapz -- Cavitation in spinal cord - Cranial part – part of vagal system - Involvement/affectation of Spinal Nucleus of CN 5  2 Nuclei: (loc: medulla oblongata) o Responsible for pain & temp on I/L face Nucleus Ambiguus Motor nucleus CNs 9, 10, 11 (cranial part) - innervates ms of the throat Nucleus Solitarius Sensory nucleus CNs 7, 9, 10 [7 – nervus intermedius] | SDJF Compilation Vagal System (cont.) DM 3, 6  Mediates many REFLEXES: ★ MG 3, 4, 6 1. Gag Reflex - 3 – ptosis 2. Vomiting Reflex / Emetic Reflex - 4 & 6 – diplopia 3. Cough Reflex TBI 3, 7, 1 [CN 1 is most affected] 4. Salivary Taste Reflex - 1 – anosmia → loss of appetite 5. Carotid Sinus Reflex - 7 – facial paralysis Review: Carotid Sinus Reflex PD 3, 7, 9 [Para: 1973 → PD: 973] Any  in Po (internal or external) →  HR (bradycardia) CN 7 MC affected CN in: C/I: elderly, may cause syncope *carotid sinus – found in bifurcation of common carotid a. - Bell’s Palsy / Prosopoplegia - Mobius o Congenital absence of ★ TRIVIAS ★ CN 7 nuclei bilaterally CN 5 Largest o Facial paralysis on both sides CN 10 Longest - Ramsay-Hunt Syndrome o Combination of - Extracranial – CN 10 Bell’s Palsy + Herpes Zoster - Intracranial – CN 4 Herpes Zoster CN 4 Longest intracranial - Shingles (painful skin lesions) Thinnest / most slender - Dermatomal distribution Only crossed - Varicella Zoster Only CN arising from dorsum of brainstem ★ - GBS ★ [GBS 7 / GMA 7] [All CN arise from anterior/ventral brainstem, except CN 4] o Ascending LE to UE to face CN 1 Shortest (affects CN 7 → facial paralysis) CN 2 Thickest myelinated [GBS – Galing Baba Symmetrical] Most affected CN in MS (optic neuritis) ★ o DDx: ALS  ICP (Papilloedema) ★ ALS – descending; fine motor skills - bulging of optic disc; complication of  ICP are initially more difficult Marcus Gunn Pupil ★ - Lyme Disease [upside down L → 7] - defect in afferent component of pupillary light reflex o “Tick”-borne pathogen Pupillary light reflex o Borrelia Burgdorferi - afferent: CN 2 - Leprosy (aka Hansen’s Dse) - efferent: CN 3 o CNs 7 & 5 CN 3 MC affected CN in: ★ affected facial ms & sensation - Weber Syndrome - Sjogren - Benedict Syndrome o CNs 7 & 9 - Syphilis (STD) → Argyll Robertson Pupil o Complication of RA [syphi-three] o Sjogren’s Triad: Syphilis Dry eyes Lacrimal gland (7) - Can cause SCI → Tabes Dorsalis Dry mouth Salivary gland (7 & 9) → Tabetic gait (ataxic gait) RA - Complication: neurosyphilis - If long-term, affects CN 3 → can - Millard-Gubler – CNs 6 & 7 lead to Argyll Robertson Pupil Argyll Robertson Pupil - Complication of neurosyphilis INDIVIDUAL DISCUSSION OF CRANIAL NERVES - Pupil that does NOT react to light, but reacts to accommodation CN1 - OLFACTORY Tabes Dorsalis  Smell [pure sensory] - DCP is affected  Anosmia Dorsal Column Pathway (DCP), fxns:  MC contused [bruised] - Proprioception o Rationale: d/t location – undersurface of brain - 2-Point Discrimination Below the brain are corrugations (irregular - Vibratory Sense surfaces). If MVA occurs → creates shearing forces that can damage CN 1  CSF Rhinorrhea 2o Basilar Skull Fx ★ CSF Rhinorrhea – CSF comes out thru nose CSF Otorrhea – CSF comes out thru ear CSF Sialorrhea – CSF comes out thru mouth Argyll Robertson Pupil | SDJF Compilation CN2 – OPTIC Note:  Vision  Fields: o Nasal / Central  Anopsia o Temporal / Peripheral Other conditions related to visual losses: (Sullivan tables)  Retina – photo receptors; loc: back of eye Myopia Impaired far vision ★  There is reversal of images, such that: Near-sightedness Nasal Retinal Fibers (N.R.F.) Temporal field of same eye Hyperopia Far-sightedness ★ Temporal Retinal Fibers (T.R.F.) Nasal field of same eye Presbyopia Age-related visual loss ★  Fibers that see the temporal field cross in the middle. Old-sightedness Meanwhile, fibers that see the nasal field does not cross. Nyctalopia Night-blindedness  Optic tract synapses with Lateral Geniculate Bodies (LGB) 2o  Vit A (Retinol) ★ o Part of thalamus important for visual relay Review: ★ Presbycusis – age-related hearing loss Lat. Geniculate Bodies Visual relay Med. Geniculate Bodies Auditory relay  Amaurosis Fugax o Monocular Blindness [one eye is blind]  Optic radiation carries the image that should be projected in o Vascular occlusion that leads to blindness the occipital area. Commonly encountered in stroke, vascular in origin  O.R. connects with Occipital Cortex – Area 17 (lobe at back) o Seen in Anterior Circulation Stroke ▪ ICA → 1st branch: ophthalmic artery ★ Visual Field Defects ★ Ant. Circulation Stroke Occlusion of ICA LESION SITE MANIFESTATION Internal Carotid Artery 1. Optic Nerve I/L Monocular Blindness Post. Circulation Stroke Occlusion of VBA 2. Optic Chiasm Bitemporal Hemianopsia ★ Vertebrobasilar Artery (Pituitary Tumor) (Loss of Peripheral Vision / Tunnel Vision)  Tested by: (Sullivan) 3. Optic Tract / C/L Homonymous Hemianopsia ★ o Snellen’s Chart (Central Visual Acuity) ★ Optic Radiation / ▪ (N) Visual Acuity = 20-20 Occipital Cortex o Confrontation Test (Peripheral Visual Acuity) ★ 4. Optic Radiation Quadrantanopsia Note: Other Tests: (Guyton) ★  Optic chiasm – assoc c pituitary tumor Ishihara Color vision testing o Pituitary gland (master gland) – loc: near O.C. Tonometry Measures Intraocular Pressure (IOP)  Quadrantanopsia – 1/4 of visual field is blind Assess glaucoma o C/L representation Retinoscopy Measure refraction errors o ex: (R) Superior Quadrantanopsia (e.g., astigmatism, hyperopia) Note:  Glaucoma – d/t  IOP → can cause blindness → peripheral vision is lost first o Optic Radiation – has 2 fibers: ▪ Upper fibers / Parietal fibers ★ VISUAL PATHWAY ★ ▪ Lower fibers / Temporal fibers Sample Questions: Q1: (R) Homonymous Hemianopsia, where is the possible lesion? a. (R) O.T. b. (R) O.N. c. O.C. d. (L) O.T. Q2: Lesion on (R) optic tract a. (R) Nasal + (R) Temporal Visual Field Loss (VFL) b. (L) Nasal + (L) Temporal VFL c. (R) Nasal + (L) Temporal VFL d. (L) Nasal + (R) Temporal VFL Q3: Pt had (L) CVA c complication of Homo. Hemianopsia. Initially, where do you put the pt’s things on his bed? a. (R) side of bed b. (L) side of bed Rationale: (L) CVA → (R) HH. INITIALLY, you must put all objects in pt’s intact visual field, which in this case is the (L) side. Q4: Lesion to upper fibers of (R) optic radiation, what is the Parts: manifestation? (L) Lower Quadrantanopsia 1. Optic Nerve (O.N.) – n. at back of eye To easily answer, just do the opposite-opposite technique. Key words: 2. Optic Chiasm/Chiasma (O.C.) – crossing in the middle - (R) → (L) 3. Optic Tract (O.T.) - Upper → Lower 4. Optic Radiation (O.R.) Q5: Lesion to temporal fibers of (L) optic radiation? 5. Occipital Cortex Area 17 (R) Upper Quadrantanopsia | SDJF Compilation CN3 – OCULOMOTOR PUPILLARY LIGHT REFLEX  PERRLA  In reflexes, they have afferent & efferent components:  Edinger-Westphal Nucleus o Afferent – CN 2 – nucleus used for the parasympathetic nervous system o Efferent – CN 3  Ptosis (aka lid lag / drooping of eyelids)  2 reflexes should be observed: o Ms affected: Levator Palpebrae Superioris ★ Direct Light Reflex Constriction of I/L eye ▪ Innervated by CN 3 Consensual / Indirect Constriction of C/L eye ▪ Elevates upper eyelid Light Reflex Responsible: CN 2 ★ Ptosis may be seen in which of the ff: a. MG ✓ b. CN 3 Palsy ✓ c. Horner’s Syndrome ✓ d. Edema d/t infection e. AOTA Testmanship: even if you’re not sure with one or more choices, but you are sure that at least 2 of the choices are correct → choose AOTA. ★ Ptosis may be seen in which of the ff: [same question but different format; fish & feather] I. MG II. CN 3 Palsy III. Horner’s Syndrome IV. Edema d/t infection Answer: still ALL  Damage causes MYDRIASIS (dilated pupil) Pupil – regulates amt of light that enters the eye Miosis Constricted pupil Mydriasis Dilated pupil When light is shone, CN 2 (afferent) will receive the information. cons-three → CN 3 damage → no more constriction → dilation Since there is too much light, it synapses c the Edinger-Westphal nucleus of CN 3 & signals it to constrict the pupil (efferent) to  Anisocoria (unequal size of pupils) regulate amt of light that enters eye – intact direct light reflex. o Bad prognosticating sign o Can be assessed thru pupillary light reflex When CN 2 receives the information, it gives off 2 impulses: one ★ Anisocoria: for the I/L CN 3 & another for the C/L CN 3. Thus, CN 2 connects c a. 3 the Edinger-Westphal nuclei of both CN 3 (R & L) – consensual / indirect light reflex. [code: chismosa si 2] b. 4 c. 5 ★ Q1: Light was shone on (R) eye; (–) D.L.R., (+) C.L.R. d. 6 What CN is affected? ★ Anisocoria: a. (R) 2 a. 3 b. (R) 3 b. 2 c. (L) 2 c. Both d. (L) 3 d. Neither Rationale: since consensual light reflex is intact, it means that CN 2 Rationale: Sullivan Tables – 2 & 3 (error); actually 3 only, since is still intact since it was able to send information to the C/L CN 3. anisocoria is defined as damage to the efferent / motor Thus, I/L CN 3 is damaged. component of the pupillary light reflex – which is CN 3. ★ Q2: Light was shone on (R) eye; (–) D.L.R., (–) C.L.R. Dynamic anisocoria may happen c CN 2 (afferent component) in the case of Marcus Gunn Pupil (pupillary escape); swinging light To confirm dx, doctor transfers pen light to (L) eye; test is used – instead of pupil constriction, dilation occurs upon (+) D.L.R., (+) C.L.R. What CN is affected? exposure to light. a. (R) 2 b. (R) 3 c. (L) 2 d. (L) 3 Rationale: once you see that consensual light reflex of one eye is also NOT intact, it means that CN 2 is affected bec it was not able to send information to both I/L & C/L CN 3. Marcus Gunn Pupil - Afferent component (CN 2) of pupillary light reflex is affected Argyll Robertson Pupil - Complication of Syphilis (Neurosyphilis) - A type of pupil that does NOT react to light, but reacts to accommodation | SDJF Compilation CN4 – TROCHLEAR & CN6 – ABDUCENS Compensations to Correct Diplopia ★ EXTRAOCULAR MUSCLES ★ Tilt 4 [count # of letters in tilt = 4; still con4ra (C/L)] Formula: EOM3LR6SO4 Rotate 6 [count # of letters in rotate = 6; still ipsix (I/L)] EOM INNERVATION (CN) INSERTION Lateral Rectus (LR) 6 Lateral sclera DDx: Tilt vs Torticollis (since they’re both common in children) Superior Oblique (SO) 4 Back of sclera How do you know if the child has diplopia & not torticollis? ★ Medial Rectus (MR) Medial sclera - Patch one eye (if pt tilts to (R), patch (L) eye [con4ra]) o if tilting corrects → diplopia Inferior Oblique (IO) Superior Rectus (SR) 3 Back of sclera Superior sclera o if tilting does NOT correct → tight SCM (torticollis) Inferior Rectus (IR) Inferior sclera ★ The ff muscles are supplied by CN 3: (fish & feather type of q) CN5 – TRIGEMINAL [trichewminal]  Largest CN ★ Only EOM inserted at the back of sclera? SO & IO (1998)  (+) Gasserian Ganglion / Semilunar Ganglion  Tic Douloureux (Trigeminal Neuralgia) CARDINAL GAZES  Mixed fxn: Motor: Muscles of Mastication [TIME / MMTL] Temporalis CLOSEs mouth (elevates jaw) Internal Pterygoid [MMT – Masseter, Med. Pterygoid, Masseter Temporalis] External Pterygoid OPENs mouth (depresses jaw) [LAt.] ★ Which ms of mastication has 2 heads? Pterygoids Medial & Lateral Pterygoids have 2 heads each. Obliques – inward action SO Down & in (look at tip of nose) IO Up & in Cardinal Gazes: [conjugate eye movements] Additional ms: ★ [except q] 1. Look to (R) - (R) LR & (L) MR 1. Digastric (Anterior belly) 2. Look to (L) - (L) LR & (R) MR 2. Mylohyoid 3. Look up & to (R) - (R) SR & (L) IO 3. Tensor Tympani [code: Tensor – Trigeminal] 4. Look up & to (L) - (L) SR & (R) IO 4. Tensor Veli Palatini 5. Look down & to (R) - (R) IR & (L) SO Sensory: Facial Sensation (3 divisions) 6. Look down & to (L) - (L) IR & (R) SO V1 – Ophthalmic Pure sensory V2 – Maxillary 2 Eye Problems assoc c EOM: V3 – Mandibular Mixed; only branch c motor fibers Diplopia [duling/libat] ★ - Double vision - Subjective complaint - Assoc CNs: 4 Vertical – SO is affected 6 Horizontal – more common Strabismus [banlag/manokon] ★ - Objective finding - Assoc CNs: 3 & 6 - 2 types: Internal/Medial Strabismus/Esotropia 6 [six / six] External/Lateral Strabismus/Exotropia 3 [three] ★ Sensory supply of eyeball: CN 5 (V1 Ophthalmic div.) The eyes have sensation, particularly the cornea of the eye. ★ Q1: Pt c/o diplopia upon looking to (R) [‘98] Cornea is the only part of the eye with NO blood supply. a. (R) 4 Corneal Reflex (Blink Reflex) b. (L) 4 - 1st discovered reflex c. (R) 6 [ipsix] - Components: d. (L) 6 Afferent 5 (V1) ★ Rationale: why I/L? When you look to (R), the (R) LR & (L) MR contracts. Efferent 7★ If (R) LR is weak, it cannot sustain its contraction towards (R). Thus, (R) eye has the tendency to be pulled medially d/t stronger MR. Eye closure – CN 7 (oribicularis oculi) ★ Q1: Pt c/o diplopia upon looking (R) & down – (L) 4 [con4ra] [‘99] Eye opening – CN 3 (levator palpebrae superioris) Rationale: why C/L? When you look (R) & down, the (R) IR & (L) SO contracts - Innervates corneal reflex: CN 5 ★ Thus, since it is the C/L SO that is contracting, C/L CN 4 is the one affected. | SDJF Compilation Sneeze Reflex CN7 – FACIAL - Components:  Bell’s Palsy / Prosopoplegia Afferent 5 (V1)  (+) Geniculate Ganglion innervates nasal mucosa; gives  Has motor, sensory & autonomic (parasympa) fxns sensation inside nose Motor: Muscles of Facial Expression Efferent 9 & 10 1. Frown - Corrugator Supercilii ★ innervates ms of pharynx; needs 2. Surprise - Occipitofrontalis forceful contraction of pharyngeal ms to expel irritants in nose 3. True Smile - Zygomaticus Major (angle of mouth is pulled lateralward & upward) Sample Q from Reviewer: 4. Grimace - Risorius Sneeze reflex involves all of the ff CN, EXCEPT: (angle of mouth is pulled lateralward) a. 5 5. Distaste - Procerus (wrinkles nose) b. 9 6. Doubt - Mentalis c. 10 7. Sneering - Levator Anguli Oris d. 1 (angle of mouth is pulled upward) Rationale: we usually think CN 1 is included bec it 8. Suck & blow - Buccinator ★ is related to olfactory, but NO, CN 1 is only used (aka trumpeter’s ms) for sense of smell. 9. Kissing - Orbicularis Oris 10. Winking - Orbicularis Oculi Correlation of Corneal & Sneeze Reflex: 11. ‘EGAD’ - Platysma When you feel like sneezing but is unable to, looking at the (shortcut for oh my god) sun may help you sneeze. That is physiologic. 10 to 40% of the population experiences that. Additional ms: Rationale: the light coming from the sun irritates the cornea 1. Digastric (Posterior belly) sending signals to the ophthalmic div. (V1) of CN 5 – which 2. Stylohyoid ★ is also connected to the nasal mucosa, thus when it senses 3. Stapedius an irritant (light), the person also sneezes + close eyes. And Stapedius that is because of the correlation of CN 5 (V1) with the - Smallest skeletal ms in body sneeze reflex & the corneal reflex (afferent component). - Attached to smallest bone: Note: stapes  Small motor fibers, bigger sensory fibers since it - If paralyzed → hyperacusis contains the gasserian ganglion → thus also making o ’d sensitivity to sound it the largest CN  Digastric Review: o Ant. belly – CN 5 Stylohyoid – CN 7 o Post. belly – CN 7 Styloglossus – CN 12 (glossus – tongue)  Mylohyoid – belongs to suprahyoid group Stylopharyngeus – CN 9 Review: Suprahyoid group – code: D MSG Sensory: taste in anterior 2/3 of tongue ★ - Digastric Chorda Tympani - Mylohyoid - fiber of CN 7 that supplies taste sensation to the - Stylohyoid ant 2/3 of tongue - Geniohyoid Ageusia Infrahyoid group – code: i-TOSS [infrahyoid-TOSS] - loss of taste sensation - Thyrohyoid - geusia → gusto - gustatory / gustation → taste - Omohyoid - Sternohyoid Gen Sensation of Tongue Taste (Pain & Temperature) - Sternothyroid Ant 2/3 7 5  Tensor Tympani o Loc: inside ear Post 1/3 9 9 o Tenses tympanic membrane (eardrum) Autonomic: supplies lacrimal & salivary glands o Dampens sound Salivary glands: (superior salivatory nucleus) ★  Tensor Veli Palatini o Tenses soft palate - Sublingual  REMEMBER: - Submandibular o Sensory of face – CN 5 Lacrimal glands o Motor of face – CN 7 (assoc c Bell’s Palsy) - Supplied by the great petrosal branch of  V3 Mandibular division – have both sensory & motor f. facial nerve (CN 7) o N. supply of ms of mastication – motor f. of - Clinical correlation: crocodile tears mandibular branch of the trigeminal nerve o Fake tears  If there is inability to close affected eye – CN 7 affected o Seen in Bell’s palsy; while pt o Recommendation: wear eye patch or eats, tears are also observed sunglasses, esp when travelling to avoid drying out of the cornea d/t wind blowing to the eye & also avoid foreign objects from entering the eye | SDJF Compilation ROUTE OF CN 7  CN 7 comes via 2 routes: ★ Q2: Lesion of CN 7 after exiting the brainstem (rare) will Pons Motor fibers manifest with which of the ff: Medulla Sensory & Parasympathetic fibers a. Hyperacusis Oblongata (called Nervus Intermedius) b. Loss of taste in ant. 2/3 of tongue c. Facial Palsy  Passes thru 3 anatomic landmarks: d. AOTA 1. Internal Acoustic Meatus Ramsay-Hunt Syndrome (Bell’s Palsy + Herpes Zoster) - where CNs 7 & 8 passes thru - Geniculate ganglion is involved/affected 2. Facial Canal - ALL structures after geniculate ganglion are affected - inside the f. canal, geniculate ganglion is formed - G. Ganglion gives off 3 branches: CVA Facial Palsy vs Bell’s Palsy Great Petrosal Lacrimal glands N. to Stapedius Hyperacusis (if paralyzed) Bell’s Palsy CN 7 Peripheral Lesion Chorda Tympani Taste in ant. 2/3 I/L Facial Paralysis CVA CN 7 Central Lesion 3. Stylomastoid Foramen C/L Lower Quadrant Facial Paralysis - MC site of facial n. compression ★ - Corticobulbar Tract (CBT) is involved ★ - CN 7 exits from skull via stylomastoid foramen o connects the CNs - CN 7 passes thru the parotid gland o bulbar = brainstem o innervated by CN 9 [P = 9] - Parotid gland – landmark before CN 7 divides into Tests: CVA Bell’s Palsy its 5 branches to the face: 1. Smile (–) on one side (–) on one side 5 Branches of CN 7: The Zebra Bumped My Car 2. Raise both eyebrows (+) (–) on one side 1. Temporal *Affectation C/L I/L 2. Zygomatic 3. Buccal 4. Mandibular 5. Cervical ★ Platysma – cervical branch of facial nerve Tapat tapat lang ang innervation ★ (+) Chvostek test [cheven] - tap parotid gland → facial ms twitching - a contraction of I/L facial ms subsequent to percussion over the facial n. ★ Q1: Lesion of CN 7 at the stylohyoid foramen will manifest with which of the ff: Ex: (R) CBT damage d/t stroke a. Hyperacusis - (L) lower quadrant of face is affected b. Loss of taste in ant. 2/3 of tongue c. Facial Palsy d. AOTA Rationale: if the peripheral n. is damaged, only distal portions from site of lesion are affected/involved; proximal are spared. Chorda Tympani is NOT affected → taste is intact. N. to stapedius is NOT affected → NO hyperacusis. Lesion @ stylohyoid f. → facial ms are affected (facial palsy). | SDJF Compilation CN8 – VESTIBULOCOCHLEAR CN10 – VAGUS  Meniere’s Dse  Longest CN  2 Parts:  Has motor, sensory & autonomic fxns 1. Vestibular Motor - Balance - Innervates ms of pharynx & ms of larynx - Vestibular Apparatus – organ for balance ★ Supplies ms of pharynx: - Manifestations when damaged: a. 9 Dysequilibrium Loss of balance b. 10 Nystagmus Rhythmic oscillation of eyes c. Both 9 & 10 Vertigo BPPV (most popular vertigo) d. NOTA 2. Cochlear Supplies ms of larynx: CN 10 - Hearing - Larynx (aka voice box) - Organ of Corti – true organ of hearing o Vocal cords – produces sound - When damaged → deafness o Phonation – sound production 3 types: [phonaTEN] ★ Conduction Problem of transmission of o Dysphonia – diff. in sound production soundwaves into ear o Aphonia – absence of sound Affects: outer/ext. ear & o Hoarse voice middle ear - Pharynx – Gag Reflex ★ Sensorineural Involvement of neural fibers o Afferent – 9 of CN 8 o Efferent – 10 Affects: inner ear - Dysphagia – difficulty in swallowing Cortical Rare; seen in CVA involving the primary cortical area for Dysphagia, what CN is affected? Cortical Deafness hearing a. 9 = (B) lesion to Affects: Area 41 b. 10 Heschl’s Gyri (primary auditory area) c. Both 9 & 10 should happen - related to Heschl’s Gyrus d. NOTA ★ Pt has dysphagia & dysphonia Area 41 – 1o Auditory Area a. 9 Area 42 – 2o Auditory Area b. 10 - Tuning Fork Tests ★ c. Both 9 & 10 Weber Lateralization of hearing loss d. NOTA Landmark: vertex of skull Rationale: phonation is only exclusive to 10 Rinne Compares air conduction with - Uvular Deviation – to determine laterality bone conduction o Deviates to stronger side Landmark: mastoid o Instruct pt to say “AHHH” o Ex: uvula deviates to (R) → ★ Test/s used for auditory acuity: (L) CN 10 problem/affectation a. Weber Sensory b. Rinne - Skin of Pinna of External Ear ★ c. Both (supplied by auricular branch of CN 10) d. Neither - Sensation to pharynx, larynx & epiglottis *auditory acuity – cochlear component of CN 8 Autonomic - 75% of parasympathetic nervous system belong to CN 10 CN9 – GLOSSOPHARYNGEAL  Has motor, sensory & autonomic fxns ★ This great parasympathetic nerve Motor innervates the thorax & abdomen – CN 10 - supplies stylopharyngeus ms - Innervates the thorax & abdomen - involved in swallowing reflex Thorax Heart ( HR) [mavagal] Sensory Lungs (bronchoconstrict) - taste & gen. sensation of post 1/3 of tongue Abdomen Stomach, liver, pancreas, Autonomic spleen, small intestine, - supplies parotid gland (inf. salivatory nucleus) large intestine Review: (GIT –  motility, digestion) Superior Salivatory Nucleus – CN 7 Inferior Salivatory Nucleus – CN 9 Review: 3 Phases of Swallowing - monitors carotid body & carotid sinus ★ 1. Oral ★ Carotid Sinus Reflex (→ vagal stimulation) 2. Pharyngeal - Afferent – CN 9 3. Esophageal - Efferent – CN 10 | SDJF Compilation CN11 – SPINAL ACCESSORY Sample Case Tongue deviates to…  2 Parts: (R) CVA (L) Cranial Part of Vagal System ★ (R) Hemiplegia (R) Joins CN 10 to innervate pharyngeal ms (R) CN 12 (R) Spinal SCM (C2, C3) – I/L side flexion, C/L rotation ★ Trapezius (C3, C4) – shoulder shrug Review:  Only CN passing thru foramen magnum - Uvula deviates to stronger side  Radical Neck Dissection ★ - Tongue deviates to weak side o CN 11 can be accidentally cut in this procedure  Lateral Winging of Scapula (Sliding Door Paralysis) ★ o Downwardly rotated o Weak trapz Review: Upward & Downward Rotation of Scapula - U.R. – serratus anterior & trapezius - D.R. – rhomboids & levator scapulae CN12 – HYPOGLOSSAL  Tongue movements  Dysarthria ★ o Problem c motor component of speech; problem c organs of articulation o DDx: Aphasia ▪ Problem c language content, comprehension, fluency, repetition o Weak tongue o Also affects CN 5, 7, 10 (parts of organs of articulation) ▪ 12 – tongue (most crucial for articulation) ▪ 5 – gums ▪ 7 – lips ▪ 10 – soft palate ★ Dysarthria: a. 12 – best answer if there is no AOTA choice b. 5 c. 7 d. 10 e. AOTA  Muscles of Tongue: [PGH-Style] Palatoglossus Tongue elevation 9, 10 Genioglossus Tongue protrusion Hyoglossus Tongue depression 12 Styloglossus Tongue retrusion/curling *Palatoglossus is supplied by the pharyngeal plexus (CNs 9 & 10).  Tongue Deviation o Deviates/points to weak side o Instruction: stick your tongue out o Ex: tongue deviates to (R) side → (R) CN 12 is affected LMNL I/L deviation UMNL C/L deviation (e.g., stroke/CVA)