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PROUDLY IN COLLABORATION WITH OSCEAZY The Cranial Nerves Station Ravanth BaskaranCranial Nerves Functions Pathology Examination Technique Case Scenarios Spot DiagnosisCranial Nerves In Order I. Olfactory II. Optic III. Oculomotor IV. Trochlear V. Trigeminal ”On Occasion Our Trusty Truck VI. Abducens Acts Funny, Very Good Vehicle VII. Facial Any How” VIII. Vestibulocochlear IX. Glossopharyngeal X. Vagus XI. Accessory XII. HypoglossalCranial Nerves Sensory or Motor Cranial Nerve Name Sensory / Motor / Both 1 Olfactory Sensory Some 2 Optic Sensory Say 3 Oculomotor Motor Marry 4 Trochlear Motor Money 5 Trigeminal Both But 6 Abducens Motor My 7 Facial Both Brother 8 Vestibulocochlear Sensory Says 9 Glossopharyngeal Both Big 10 Vagus Both Brains 11 Accessory Motor Matter 12 Hypoglossal Motor More Cranial Nerves Functions I. Olfactory – Sense of smell II. Optic – Vision III. Oculomotor – Eye movement (medial/superior/inferior rectus, inferior oblique muscles) , levator palpabrae muscle that helps to raise eyelid IV. Trochlear – Eye movement (superior oblique muscle = SO4) V. Trigeminal – 3 branches (V1 = ophthalmic, V2 = maxillary, V3 = mandibular), sensation of face, muscles of mastication VI. Abducens – Eye movement (lateral rectus muscle) VII. Facial – Muscles of facial expression, taste to anterior 2/3 tongue VIII. Vestibulocochlear – Hearing, balance IX. Glossopharyngeal – Taste to posterior 1/3 tongue, sensation to pharynx X. Vagus – Regulation of internal organ functions, such as digestion, heart rate, and respiratory rate XI. Accessory – Trapezius & sternocleidomastoid muscles XII. Hypoglossal – Tongue musclesSTUDENT INSTRUCTIONS Student Briefing Setting: You are on clinical placement in General Practice Mr Roy, a 69 year old male presents with a sudden loss of vision Patient Details: Task: Please Perform an examination of the appropriate Cranial NervesCRANIAL NERVES EXAMINATION WIPPE Both you and the patient seated, 1m away from each other, with eyes on the same level CRANIAL NERVE 1 Olfactory nerve • Any change in smell • Assess the nostril and its surroundings • Trigeminal nerves pick up noxious stimuli via sensory fibres whilst avoiding strong scents • If anosmia detected consider: nasal polyps and mucosal thickening https://www.mdpi.com/1422-0067/18/2/287 CRANIAL NERVE 1 Olfactory nerve Pathology • Change in sense of smell – anosmia, hyposmia • Causes of dysfunction: • Age, Infection, Allergic oedema of nasal mucosa • Trauma, Drugs • Parkinson’s disease CRANIAL NERVE 2 Optic nerve • Inspection to see pupil - size, shape, colour and external features ● Wear glasses ● Cover one eye and and place patient 6m away ● Move down the chart and see the level at which the patient can’t read anymore ● Move closer if patient can’t see at 6m Distance of chart (m) ● Exclusion criteria of a line: more than 2 letters CRANIAL NERVE 2 Optic nerve ● Ensure glasses are worn ● Cover unilateral eye ● Start off with a test plate and follow up with the other plates provided (12) CRANIAL NERVE 2 Optic nerve Visual Fields Blind spot • Cover the contralateral eye that the ● Ask patient to focus on your face patient cover ● Assess patient’s blind spot by • Ask patient to look at you (fixed point) comparing it to your own • Slowly move your finger from ● The blind spot is there you do not see the object you are holding peripheral vision in ● Object needs to be equidistant • Hand needs to be equidistant between you and patient between both https://www.scientificamerican.co m/article/find-your-blind-spot/ CRANIAL NERVE 2 Optic nerve Direct Pupil Reflex Consensual Pupillary Reflex ● Assessing the eyes response to ● Assessing the contralateral eyes light response to light ● When a light is shone into the eye ● When a light is shone into one eye, 100% of the pupil must constrict the other eye must constrict CRANIAL NERVE 2 Optic nerve Accommodation Reflex Visual neglect ● Ask patient to look far away ● 1 metre from the patient ● Ask patient to look at your finger ● Ask patient to look at you (fixed point) ● See the accommodation of the pupil ● Hold your finger out to the corner of via constriction patient’s vision field and wiggle them individually and together R Relative A Afferent P Pupillary Defect D Swinging Light Test • Warn patient you are going to get very close (?COVID) • Useful to place hand on patient’s forehead to know your bearings • Use your right eye to examine their right eye (prevent you kissing the patient!) • Begin by identifying a blood vessel and follow into review/how-to-use-the-direct-ophthalmoscope/ &ic-ophthalmology- https://stanfordmedicine25.stanford.edu/the25/fundoscopic.html • Assess optic disc – colour, margin, cupping Fundoscopy • Assess retinal vessels for pathology (e.g. arteriovenous nipping, neovascularisation, haemorrhages) • Assess macula by asking patient to look directly into the light (e.g. cherry red spot = central retinal artery occlusion) • MUCH easier if pupil has been dilated (e.g. with Tropicamide)Spot Diagnosis Central Retinal Vein Occlusion Central Retinal Artery Occlusion Papilledema Wet Age-related Macular Degeneration Dry Age-related Macular DegenerationSpot Diagnosis Central Retinal Vein Occlusion Central Retinal Artery Occlusion Papilledema Wet Age-related Macular Degeneration Dry Age-related Macular DegenerationSpot Diagnosis Central Retinal Vein Occlusion Central Retinal Artery Occlusion Papilledema Wet Age-related Macular Degeneration Dry Age-related Macular DegenerationSpot Diagnosis Central Retinal Vein Occlusion Central Retinal Artery Occlusion Papilledema Wet Age-related Macular Degeneration Dry Age-related Macular DegenerationSpot Diagnosis Central Retinal Vein Occlusion Central Retinal Artery Occlusion Papilledema Wet Age-related Macular Degeneration Dry Age-related Macular DegenerationSpot Diagnosis Central Retinal Vein Occlusion Central Retinal Artery Occlusion Papilledema Wet Age-related Macular Degeneration Dry Age-related Macular DegenerationSpot Diagnosis Normal Glaucoma Diabetic Retinopathy Papilledema Hypertensive RetinopathySpot Diagnosis Normal Glaucoma Diabetic Retinopathy Papilledema Hypertensive RetinopathySpot Diagnosis Normal Glaucoma Diabetic Retinopathy Papilledema Wet Age-Related Macular DegenerationSpot Diagnosis Normal Glaucoma Diabetic Retinopathy Papilledema https://www.pediatricophthalmologypa.com/d Macular Degeneration eye-library-5/glaucoma-medical-image-of- fundus-retina-showing-optic-disc-cupping- jpg-2/ Cranial Nerve 2 Pathology – Visual Field Loss Bi-Temporal Hemianopia • The main points for the exam are: • Left homonymous hemianopia means visual field Craniopharyngioma defect to the left, i.e. Lesion of the right optic tract • Homonymous quadrantinopias: PITS (Parietal- Optic chiasm Inferior, Temporal-Superior) • Bitemporal hemianopia = Lesion of optic chiasm - classically pituitary adenoma Pituitary Adenoma Picture Credit: https://www.sciencedirect.com/topics/medicine-and-dentistry/homonymous-hemianopsiaCranial Nerve 2 Pathology – Visual Field Loss CN 3, 4, 6 Examine eyelids for any deformities Eye movements: H-test The patient is asked to keep their head still and follow your finger with their eyes as you move your finger in an “H” pattern Ask the patient if they get any double vision (if yes, there may be an impairment with CN III) Pause laterally to look for nystagmus Pause vertically for fatigability It is important to stay approximately 30 cm away from the patient when the H test conducted Observe any restriction in eye movement SO4, LR6, Everything else CN3 Cranial Nerve 3 Pathologies • Palsy results in (ipsilateral): • Ptosis – loss of innervation to levator palpebrae superioris muscle that raises eyelid • 'Down and out' eye • Dilated, fixed pupil on same side as injury (‘surgical’ palsy) – loss of function of parasympathetic innervation to sphincter pupillae • Ptosis + dilated pupil = third nerve palsy • Ptosis + constricted pupil = Horner's syndromeCranial Nerve 3 Palsy VS Horner’s Syndrome Pupils Eyelids CN3 Palsy Horner’s CN3 Palsy Horner’s Levator Palpibrae Muller’s Muscle Parasympathetic supply Sympathetic supply Superioris Unopposed Sympathetic Unopposed function Parasympathetic function Eyelid elevation Eyelid elevation Fixed Dilated Pupil Pupil constriction Ptosis (Miosis) Sphincter Pupillae vs Dilator Pupillae Medical Parasympathetic ● Microvascular disease (e.g. sympathetic diabetes, hypertension) CN3 • Trauma (extradural or subdural VS haemorrhage; fracture in the cavernous sinus) • Aneurysm in the posterior communicating artery at junction with • Raised ICP can cause a third nerve palsy due to herniation Surgical Surgical Medical ○ Parasympathetic nerve fibres ○ Medical third nerve palsies (e.g. (that constrict pupil) located diabetes) tend to affect on outside of nerve, therefore central nerve fibres earlier than peripheral fibres, things that ‘crush’ nerve therefore rarely present with cause pupillary involvement (i.e. pupillary involvement as ‘surgical’ causes) parasympathetic nerve fibres that constrict pupils are ○ Third nerve palsy (ptosis, ‘down Parasympathetic located on periphery and out’ eye) presenting with an enlarged pupil = surgical ○ There is better vascularization of cause… therefore CN3 urgent brain imaging (CT the periphery of the head/angiogram to rule out nerve, so functions for longer – still present with ptosis, bleed/aneurysm) ‘down and out’ eye Cranial Nerve 4 Pathologies ● Palsy results in defective downward gaze → vertical diplopia ○ Classically noticed when reading a book or going downstairs ○ The patient may develop a head tilt, which they may or may not be aware ○ When looking straight ahead, the affected eye appears to deviate upwards and is rotated outwards = ‘Up and out’ eye ● Potentially caused by head trauma Cranial Nerve 6 Pathologies • Palsy results in defective abduction → horizontal diplopia • Double vision when looking to one side (affected eye does not go passed the midline), head turn towards the affected eye • Potentially caused by raised intracranial pressure Picture Credit: https://www.scielo.br/scielo.php?pid=S0034-72802013000100014&script=sci_arttext&tlng=enInternuclear Ophthalmoplegia (INO) • A cause of horizontal disconjugate (i.e. not paired) eye movement • Due to a lesion in the medial longitudinal fasciculus, which connects the 3 , 4 th th and 5 cranial nuclei • Coordinated eye movements (keeping single binocular vision) maintained by medial longitudinal fasciculus (MLF), i.e. allow communication between CNVI and CNIII for alternate eyes in horizontal eye movement • Lesions cause an internuclear ophthalmoplegia • Causes nystagmus in opposite eye (as it tries to work hard to compensate for eye not moving)Internuclear Ophthalmoplegia (INO) CN3, CN3, Oculomotor Oculomotor MIDBRAIN MLF MLF CN6, CN6, Abducens Abducens PONSInternuclear Ophthalmoplegia (INO) ● Features: ○ Impaired adduction of the eye on the same side as the lesion ○ Horizontal nystagmus of the abducting eye on the contralateral side ○ In a right-sided INO there is impaired adduction of right eye with horizontal nystagmus of the abducting left eye on voluntary left gaze ○ Failure of adduction in both eyes signifies a bilateral internuclear ophthalmoplegia ● Causes: ○ Multiple sclerosis ○ Vascular disease Cranial Nerve 5 Examination • The sensory component of • The jaw jerk reflex is a stretch each division is tested by reflex that entails tapping rubbing cotton wool on the forehead, malar eminence and below the patients chin while their mouth is open. lower face over the mandible respectively • Corneal reflex can also be • Sensation is compared on tested - this involves gently either side • The motor component of V3 is touching the cornea using cotton wool to see where tested by examining the there is involuntary blinking muscles of mastication of the eyelids (temporalis, masseter and pterygoids) • This is tested by asking the patient to clench their jaw to assess muscle bulk and open mouth against resistance Cranial Nerve 5 Pathologies • Trigeminal neuropathy causes: • Idiopathic (Bell’s palsy equivalent) • Cavernous sinus syndrome (only V1 and V2 branches) • Cerebellopontine angle (cerebellum + pons) • Acoustic neuroma, chronic meningitis • Inflammatory – SLE, systemic sclerosis, Sjögren’s syndrome • Trigeminal neuralgia: • Severe unilateral facial pain • Brief electric shock-like pains, abrupt in onset and termination • Pain evoked by light touch – shaving, washing, brushing teeth • Treatment is with carbamazepine or surgical decompressionSTUDENT INSTRUCTIONS Student Briefing Setting: You are on clinical placement in General Practice Ms Kent, a 82 year old Female presents with a sudden facial Patient Details: droop Task: Please Perform an examination of the appropriate Cranial Nerves Cranial Nerve 7 Examination Face, Ear , Taste, T ear • Look for signs of reduced facial tone (e.g. drooping of mouth) • Facial movement – raise eyebrows, close eyes as tightly as possible, puff out cheeks, show gums • Examiner can test against resistance – e.g. try to open eyes, try to ‘burst’ cheeks • Ask about any changes in taste • Offer to test corneal reflex Facial Nerve Palsy UPPER MOTOR NEURON VS LOWER MOTOR NEURON CORTEX BRAINSTEM IDIOPATHIC: BELL’S PALSY Cranial Nerve 7 Pathologies ● Special visceral efferent ● Muscles of facial expression ● General visceral efferent ● Lacrimation, Salivary and Mucosal glands ● Special visceral afferent ● Loss of taste in the anterior ⅔ of the tongue ● General somatic afferent ● HyperacusisSpot Diagnosis Right Conductive Hearing Loss A patient presents with hearing loss on Right Sensorineural Hearing Loss the right. You conduct a Rinne’s and Weber’s test and notice that bone conduction is > air conduction on the Left Conductive Hearing Loss right ear and the weber’s test lateralised to the Right. What is the most likely Left Sensorineural Hearing Loss pathology? Mixed Hearing LossSpot Diagnosis Right Conductive Hearing Loss A patient presents with hearing loss on Right Sensorineural Hearing Loss the right. You conduct a Rinne’s and Weber’s test and notice that bone conduction is > air conduction on the Left Conductive Hearing Loss right ear and the weber’s test lateralised to the Right. What is the most likely Left Sensorineural Hearing Loss pathology? Mixed Hearing LossSpot Diagnosis Mixed Hearing Loss Ms Smith and 60 year old Female Right Sensorineural Hearing Loss presents with partial hearing loss in both ears. You conduct a Rinne’s test and notice that air conduction > bone Left Sensorineural Hearing Loss conduction. The Weber’s test does not lateralise. What is the most likely Bilateral Conductive Hearing Loss pathology? Bilateral Sensorineural Hearing LossSpot Diagnosis Mixed Hearing Loss Ms Smith and 60 year old Female Right Sensorineural Hearing Loss presents with partial hearing loss in both ears. You conduct a Rinne’s test and notice that air conduction > bone Left Sensorineural Hearing Loss conduction. The Weber’s test does not lateralise. What is the most likely Bilateral Conductive Hearing Loss pathology? Bilateral Sensorineural Hearing Loss Cranial Nerve 8 Examination • Gross hearing – objective measure of hearing can be achieved by occluding other ear’s tragus and whispering a number at 60cm away from other ear (arm’s length), at 30cm and right next to ear • Rinne’s/Weber’s test • Vestibular system – Ask the patient to march on the spot with their arms outstretched and their eyes closed: • Normal result: same position • Vestibular lesion: turn towards the side of the lesion Rinne's test Cranial Nerve 8 Examination Weber's test • Tuning fork should be 512 Hz • Tuning fork should be 512 Hz • Weber's test = Tuning fork is placed in the • Rinne's test = Tuning fork is placed over middle of the forehead equidistant from the mastoid process until the sound is no the patient's ears longer heard, followed by repositioning • The patient is then asked which side is just over external acoustic meatus loudest • Air conduction (AC) is normally better • In unilateral sensorineural deafness (e.g. than bone conduction (BC) acoustic neuroma), sound is localised to • If BC > AC, then conductive deafness the unaffected side • Rinne sounds like Rinna = Pinna, • In unilateral conductive deafness (e.g. therefore place on mastoid process otosclerosis), sound is localised to the affected side CONDUCTIVE HEARING LOSS SENSORINEURAL HEARING LOSS USUAL AGE OF ONSET YOUNG MIDDLE AGE/ ELDERL Y WHERE IS THE PROBLEM? EXTERNAL/ MIDDLE EAR INNER EAR/ NERVES NOISY ENVIRONMENTS WORSEN HEARING NOISY ENVIRONMENTS IMPROVE HEARING CLINICAL LOSS OF HIGH FREQUENCIES (DISTORTED) FEATURES SOUND IS NOT DISTORTED OFTEN TINNITUS PRESENT MENIERE’S DISEASE OTOSCLEROSIS OTITIS MEDIA ACOUSTIC NEUROMA CAUSES CERUMEN IMPACTION NOISE-INDUCED HEARING LOSS WEBER TEST LATERELISES TO DISEASES EAR LATERELISES TO NORMAL EAR RINNE TEST BONE CONDUCTION > AIR CONDUCTION AIR CONDUCTION > BONE CONDUCTION (BOTH ↓) RIGHT LEFT EITHER CONDUCTIVE HEARING LOSS IN RIGHT EAR OR SENSORINEURAL HEARING LOSS IN LEFT EAR RIGHT LEFT EITHER CONDUCTIVE HEARING LOSS IN LEFT EAR OR SENSORINEURAL HEARING LOSS IN RIGHT EAR SPOT DIAGNOSIS A 25 YEAR OLD WOMAN PRESENTS WITH 2 WEEKS OF RIGHT ARM WEAKNESS. A FEW MONTHS AGO SHE HAD A NUMBER OF Multiple Sclerosis WEEKS OF PAIN ON MOVING HER EYES BUT THIS SETTLED BY ITSELF. A 62 YEAR OLD WOMAN PRESENTS WITH A DROOPING LEFT EYELID AND A SMALL LEFT PUPIL. HER LEFT EYE ALSO APPEARS TO HAVE Horner’s Syndrome ‘SUNKEN’. SHE HAS 40 PACK YEAR SMOKING HISTORY. A 50 YEAR OLD MAN PRESENTS WITH ALTERED SENSATION IN HIS FACE, BILATERAL HEARING LOSS, FULLNESS IN HIS BOTH HIS EARS, A CONSTANT Neurofibromatosis Type 2 RINGING IN HIS EARS, DIFFICULTIES MOVING HIS FACE AND PROBLEMS WITH WALKING NORMALLY. A 65 YEAR OLD WOMAN PRESENTS WITH DIFFICULTIES RAISING HER SHOULDERS AND TURNING HER HEAD. Accessory A 65 YEAR OLD WOMAN PRESENTS WITH A FEVER, NEW-ONSET COUGH AND SEVERE SHORTNESS OF BREATH. SHE DOES NOT BELIEVE IN VACCINATIONS. ON Olfactory QUESTIONING SHE SAYS HER SENSE OF SMELL HAS BEEN MISSING FOR 2 WEEKS. Cranial Nerve 9, 10 Examination • Ask the patient if they have experienced any issues with swallowing, as well as any changes to their voice or cough • Ask the patient to open their mouth and ask the patient to say “ahh“: A vagus nerve lesion will causes uvula deviation away from the lesion • Swallow assessment: palatini muscle • Ask the patient to take a sip of water and observe the patient swallow – an ineffective swallow which can be caused by both glossopharyngeal (afferent) and vagus (efferent) nerve pathologyCranial Nerve 9, 10 ● Speech problems Pathologies ● Swallowing problems ● Breathing problems Cranial Nerve 10 Cranial Nerve 9 ● Swallowing ● Dysphagia difficulty ● Hoarseness ● May remain ● Dyspnoea asymptomatic ● Tachycardia Cranial Nerve 11 Examination • Shrug shoulders against resistance (Trapezius muscle) • Turn head against resistance (Sternocleidomastoid muscle) Pathologies ● Weakness in head rotation - Sternocleidomastoid ● Shoulder elevation - Trapezius muscle Cranial Nerve 12 Examination • Inspect the tongue for wasting and fasciculations at rest • Ask the patient to protrude their tongue and observe for any deviation (which occurs towards the side of a hypoglossal lesion) • Assess power of tongue muscles – Place your finger on the patient’s cheek and ask them to push their tongue against it (weakness would be present on the side of the lesion) Cranial Nerve 12 Pathologies ● Wasting of the ipsilateral tongue muscle on the same side of the lesion ● Paralysis, fasciculation ● On protrusion, tongue will deviate to the side of the lesionConcluding Statement • Thank patient, wash hands • Summarise findings – any positive findings and important relevant negatives • Offer to perform corneal reflex and gag reflex tests • To complete exam: Fundoscopy & otoscopy + upper limb/lower limb neurological examination Tips For All Physical Examinations LOOK 01 03 WIPE 05 BE SYSTEMATIC For general inspection, LOOK atAlways perform WIPE BE SYSTEMATIC and try to the patient and around the bed look slick for a good few moments WORDING RIGHT SIDE SHOWTIME! 02 04 06 PUT ON A When talking in between the right sideom the patient’s SHOW! examination, say ‘’there is no looking for …’’ rather than ‘’I amPLEASE FILL OUT THE FEEDBACK FORM PLEASE TUNE IN TO OUR REMAINING SESSIONS THIS WEEK