The document provides information on examining the 12 cranial nerves. It describes testing various functions for each nerve including smell, vision, eye movements, facial sensation and movement, hearing, taste, swallowing and neck movement. Examinations include identifying smells and visual acuity, checking eye movements, testing facial muscle strength and sensation.

1. Cranial Nerve Examination Irfan Ziad MD UCD drkupe.blogspot.com

2. CN2 :Optic CN1 :Olfactory CN3 :Oculomotor CN4 :Trochlear CN5: Trigeminal CN6 :Abducens CN7 :Facial CN8: Vestibulocochlear CN9: Glossoparyngeal CN10: Vagus CN11: Accessory CN12: Hypoglossal midbrain pons medulla Anterior aspect of midbrain Dorsal aspect of midbrain

3. Inspection Position the patient sitting over the edge of the bed Look for : Scars (eg. craniotomy), pupil equality, facial asymmetry, ptosis, proptosis, neurofibromas Hi, my name is _____. Can I examine you?

4. CN I CN 1 Olfactory Nerve

5. Have you ever noticed any change in sense and smell? You ask the patient “ Have you ever noticed any change in sense and smell?” If the answer is NO, proceed to the next CN Smell CN I CN 1 Olfactory Nerve

6. If the answer is YES, Test: occlude one nostril, close eyes, identify smell (mint, coffee) Anosmia- loss of the sense of smell (eg. flu, nasal polyps) Lesion- nose, cribiform plate of the eythmoid bone, base of skull- eg meningioma, early sign of parkinson. Smell CN I Can you tell me what smell is this? CN 1 Olfactory Nerve

7. CN II Optic canal CN 2 Optic Nerve

8. Ask patient do they have any difficulty with their vision. “ Can you see the clock on the wall?” “ Can you read the newspaper?” Ask the pt whether she’s myopic (nearsighted) or hyperopic(farsighted) Visual Acuity Can you see the clock on the wall? CN II CN 2 Optic Nerve

9. Snellen chart is hold at arm-length A portable Snellen’s chart will enable you to perform a more formal test A patient who is having visual problems should be asked to count fingers held up in front of each eye in turn, and if this is not possible then perception of hand movement should be assessed. Failing this, light perception only may be present Visual Acuity CN II Test acuity with her glasses on. Pinhole if she forgets her glasses CN 2 Optic Nerve

10. Confrontation test : ask the pt to look into your eyes while you place our index finger just outside the outer limits of your temporal fields. Move the fingers in turn and then together. “ Point to the moving finger” In visual inattention (parietal lobe lesions) the patient will only point to one finger when you move both simultaneously. Point to the moving finger Visual Field CN II CN 2 Optic Nerve

11. Test her peripheral field on each eye separately. “ Can you see the whole of my face?” Can you see the whole of my face? Visual Field CN II CN 2 Optic Nerve

12. Keep looking at my nose, tell me when you see my finger moves Visual Field Test her left temporal vision against your right temporal vision by moving your wagging finger from the periphery towards the centre “ Tell me when you see my finger moves” The temporal field should be tested in the horizontal plane and in the upper and lower temporal quadrants. Change hands and repeat on the nasal side CN II CN 2 Optic Nerve

13. Bitemporal hemianopia : causes: optic chiasm lesion, pituitary tumour, craniopharyngioma Right optic nerve lesion Left Homonymous hemianopia Left Superior Quadrantanopia Left Inferior Quadrantanopia Left homonymous scotoma 2a 2b 2b 1 2 3 4 2+2a 5 6 7 2a+2b Binasal hemianopia : Very rare Left Homonymous hemianopia with macular sparing Visual Field Level of lesions CN II CN 2 Optic Nerve

14. Arcuate scotoma- moderate glaucoma Unilateral defect found with arterial occlusion, branch retinal vein thrombosis and inferior retinal detachment Central scotoma- macular degeneration or macular oedema Lesions at the level of the retina These affect one eye only Visual Field CN II CN 2 Optic Nerve

15. Tell the pt to look at the tip of your nose. Move the red-headed pin from the temporal periphery through the central field to the nasal periphery, asking the patient “ tell me when the red pin disappears, and reappears.” “ tell me when the red pin disappears and reappears.” The blind spot enlarges with papilloedema e.g. raised intracranial pressure with brain tumour. Demyelination of the optic nerve in multiple sclerosis can cause loss of central vision Blind Spot CN II CN 2 Optic Nerve

16. This is affected in colour blindness and optic neuritis (loss red colour first). CN II Colour Vision Test is done with an Ishihara plate CN 2 Optic Nerve

17. Fundoscopy Turn on, set diopters to zero, focus on specific distance, look for red reflex, adjust if pt wear glass, look for blood vessels, follow, look at optic disc- clear or blurred? - Hypertensive, diabetic, papillodema, optic neuropathy, pigmentation (mithocondrial disorder, retinotitis pigmentosa) CN II CN 2 Optic Nerve

18. Extraocular movements CN III, IV, VI From oculomotor nucleus CN 3,4.6 Oculomotor, Trochlear, Abducens Nerve

19. Pupillary light reflex Direct and Consensual : Put your hand in between the patient’s eyes. With a pocket torch shine the light from the side. Do a swinging-light test. Normally, the pupil into which the light is shone constricts rapidly (Direct light reflex) Simultaneously the other pupil constricts in the same way, (Consensual light reflex) Repeat this procedure on the other side RAPD (Relative Afferent Pupillary Defect) previous optic neuritis)- swinging light test- damaged nerve dilate in response to light Causes: eg previous optic neuritis Oculomotor Nerve CN III CN 3

20. Accommodation reflex “ Look at that mark on the wall, now look at my finger” “ Look at that mark on the wall, now look at my finger” Examine the pupils for size, shape, equality and regularity PERRLA : Pupils Equal, Round, Reactive to Light and Accommodation Pathology Unilateral dilated pupil - drugs- cocaine, eye drops (mydriatic) - 3rd nerve palsy- any associated ptosis, strabismus - Holes-Adie pupil- pupil reacts sluggishly, associated with syphilis -Absent light reflex with an intact accommodation reflex occurs in Argyll Robertson pupil in neurosyphilis Oculomotor Nerve CN III CN 3

21. Assess for eye movement, diplopia [double vision] and nystagmus Ask the patient to look laterally left and right, continue moving the finger to complete H pattern. Tell the patient to inform you if they see double images [diplopia] Diplopia is an early sign of ocular muscle weakness Without moving your head, follow the pin with your eye. Tell me if you see double Extraocular movements CN 3,4.6 Oculomotor, Trochlear, Abducens Nerve

22. Extraocular movements SR SR IR IR IO MR LR LR SO LR – Lateral Rectus MR – Medial Rectus SR- Superior Rectus IR- Inferior Rectus IO- Inferior Oblique SO- Superior Oblique CN IV supplies SO CN VI supplies LR CN III supplies all others + levator palpebrae superioris (which elevates the superior eyelids) CN 3,4.6 Oculomotor, Trochlear, Abducens Nerve

23. Complete ptosis Eye down and out Dilated pupil which is not responsive to light and accommodation. Double vision going down stairs or reading books Ask patient to turn the eye in and then to look down- may cause vertical hypertropia (pic) Failure of lateral movement Nystagmus. 3 rd nerve palsy 4 th nerve palsy 6 th nerve palsy Extraocular movements Nystagmus The direction of nystagmus is defined as that of the fast [correcting] movement Vestibular lesion – nystagmus away from the side of the lesion Cerebellar lesion – nystagmus to the side of the lesion Internuclear ophthalmoplegia Abducting eye has greater nystagmus than the adducting eye. Problems btw nuclear, 3rd n 6th connected by medial longitudinal fasciculus (MLF) - MS CN 3,4.6 Oculomotor, Trochlear, Abducens Nerve

24. Trigeminal Nerve CN V Sensory branch Ophthalmic (V1) Maxillary (V2) Mandibular (V3) Motor Muscle of mastication Masseter Temporalis Medial pterygoid Lateral pterygoid Tensor veli palatini mylohyoid Anterior belly of digastric Tensor tympani Others All involved in biting, chewing, swallowing except for tensor tympani which acts to dampen sound produced from chewing Masseter Temporalis Trigeminal Nerve CN 5

25. Test for soft touch using cotton wool - sternum first, close eyes in the 3 divisions of the nerve V1- ophthalmic- forehead up to the top of the head V2- maxillary V3- mandibular (up to angle of the jaw) The patient should be instructed to say “yes” each time the touch of the cotton wool is felt. Do not stroke the skin touch it. Test for pain using sharp object. Ask patient does it feel sharp or dull Causes of sensory problems - MS- MS plaque in the brainstem in young people - Sjogren- dry eyes, dry mouth -Trigeminal neuralgia- older people Facial Sensory Say “yes” if you feel this Trigeminal Nerve CN V CN 5

26. Ask the pt to look up and away, touch the corneal. Reflex blinking of both eyes is a normal response. Pathology Bell’s palsy- unable to blink due to damage to the efferent limb (CNVII) CNV forms the afferent limb Corneal Reflex I’m going to gently touch your eye with a cotton bud. Trigeminal Nerve CN V CN 5

27. Inspect for wasting of the temporal and masseter muscles Ask patient to clench their teeth and palpate for contraction of the temporal and masseter muscles Motor Can you grit your teeth, please? Trigeminal Nerve CN V CN 5

28. Ask patient to open their mouth and hold it open while the examiner attempts to force it shut [pterygoid muscles]. A unilateral weakness of the motor division causes the jaw to deviate towards the weak side.If weakness is suspected patients should be asked to move the jaw laterally against resistance. The jaw can be moved towards the affected muscle but cannot move towards the normal side. Motor Open up your mouth and hold it for me Trigeminal Nerve CN V CN 5

29. Ask the pt to open her mouth fully, and close halfway, , place index finger on her chin and tap with a patella hammer, if jaw jerk is highly exaggerated. Help to distinguish btw pseudobulbar palsy (UMN lesion of lower cranial nerve 9, 10,11,12) and a bulbar palsy (LMN lesion of lower cranial nerve 9,10,11,12) The Jaw Jerk I’m going to gently tap your jaw Trigeminal Nerve CN V CN 5

30. CN VII Facial canal (tortuous course) Internal auditory meatus Geniculate ganglion Stylomastoid foramen Temporal Zygomatic Buccal Mandibular Cervical Major facial branches Inside Skull Outside skull Other Posterior auricular nerve Posterior belly of Digastric Stylohyoid muscle Stapedius Frontalis, orbicularis oculi Z1: Eye & around orbit Z2: Mid face & smile Buccinator, upper lip Lower lip, orbicularis oris Platisma controls scalp muscles around the ear 3. SENSORY 2. PARASYMPATHETIC Greater petrosal to Lacrimal gland, sphenoid sinus, frontal sinus, frontal sinus, maxillary sinus, eithmoid sinus, nasal cavity, The facial nerve has four components: 1. BRANCHIAL MOTOR 4. TASTE From facial nerve nucleus Small contribution to external acoustic meatus Palate via greater petrosal Ant 2/3 tongue via chorda tympani From Nevus Intermedius Petrous temporal bone CN 7 Facial Nerve

31. Ask the patient to shut the eyes tightly Observe and try to force open each eye. If a lower motor neuron lesion is detected [weakness on one side of face], check for ear and palatal vesicles of herpes zoster of the geniculate ganglion – the Ramsay Hunt syndrome Motor Shut your eyes tightly and don’t let me open them CN VII CN 7 Facial Nerve

32. Ask patient to look up and wrinkle her forehead. Feel for muscle strength by pushing down on forehead. This movement is preserved on the side of an upper motor neurone lesion [a lesion which occurs above the level of the brainstem nucleus], because of bilateral supranuclear innervation giving some compensation to the upper face which is not the case in LMN lesion (Bells palsy/Ramsay Hunt- Herpes Zoster) The remaining muscles of facial expression are usually affected on the side of an UMN lesion. In a LMN lesion all muscles of facial expression are affected on the side of the lesion. Motor Wrinkle your forehead for me please CN VII CN 7 Facial Nerve

33. Ask the patient to show their teeth Compare the nasolabial grooves which are smooth on the weak side. Left upper motor neuron seventh nerve lesion leads to drooping of the corner of the mouth, flattened nasolabial fold, and sparing of the forehead on the left side** Motor Show me your teeth CN VII CN 7 Facial Nerve

34. Ask the patient blow out her cheeks Motor Blow out your cheeks CN VII CN 7 Facial Nerve

36. CN VIII Cochlear division- Hearing From organ to Corti in cochlea Hair cells to cell bodies in spiral ganglion (in modiolus) To 2 cochlear nuclei (ventral & dorsal) Vestibular division – Balance From semicircular canals, utricle & saccule Cell bodies in vestibular ganglion in outer part of internal acoustic meatus To 4 vestibular nuclei (medial, lateral, superior, inferior) CN 8 Vestibulo-Cochlear Nerve

37. Any problem with hearing? Hearing aids? Mask- cover the tragus of the ear and whisper a number, ask pt to repeat If deafness is suspected perform Rinne’s test and Weber’s test Hearing+Balance I’m going to whisper a number. I want you to repeat it. CN VIII CN 8 Vestibulo-Cochlear Nerve

38. Rinne’s Test Rinne- base of tuning fork on the mastoid process, “ tell me when it stops”, then bring it to the ear, “ Can hear it? “ With nerve deafness the note is audible at the external meatus, as air and bone conduction are reduced equally, so that air conduction is better as is normal. This is termed Rinne-positive. With conduction [middle ear] deafness no note is audible at the external meatus. This is termed Rinne-negative. Can you hear it? CN VIII CN 8 Vestibulo-Cochlear Nerve

39. Weber’s Test A vibrating tuning fork is placed on the centre of the forehead. Normally the sound is heard in the centre of the forehead. With nerve deafness the sound is transmitted to the normal ear. With conduction deafness the sound is heard louder in the abnormal ear. Patients with defective hearing should be referred for audiometry. This measures the degree of hearing loss at different sound frequencies. Can you hear it? CN VIII CN 8 Vestibulo-Cochlear Nerve

40. CN IX CN 9 Glossopharyngeal Nerve

41. CN X CN 10 Vagus Nerve

42. CN IX, X CN 9, 10 Glossopharyngeal and Vagus Nerve

44. CN XII Its nucleus receive Corticonuclear fibers from both cerebral hemispheres, but the cells supplying the genioglossus muscle receives corticonuclear fibers only from the opposite cerebral hemisphere It supplies 1. All the intrinsic muscles of the tongue 2. Styloglossus 3. Hyoglossus 4. Genioglossus 5. Doesn’t supply Palatoglossus – Supplied by the vagus Function is to control the movement of the tongue In the upper part, the Hypoglossal nerve is supplied by the C 1 fibers CN 12 Hypoglossal Nerve

45. CN XII Motor Nerve of Tongue Observe the tongue at rest- wasting? on one side? fasciculation? Stick out tongue straight- deviate to one side? Tongue deviate to the side of a lesion of CNXII Wiggle tongue side-to-side - (coordination)altered in cerebellar disorder Wiggle your tongue side-to-side CN 12 Hypoglossal Nerve

46. CN XI Cranial Root Spinal Root Receives corticonuclear fibers from both cerebral hemispheres It joins the spinal root & leaves the skull through jugular foramen Then the roots separate again, cranial root joins the vagus Situated in the anterior grey column of the spinal cord in the upper 5 cervical segments Nerve fibers emerge from the spinal cord & form a nerve trunk that ascends into the skull through the foramen magnum Spinal part joins the cranial part & pas through the jugular foramen Then they separate again Supply the muscles of: Soft palate ( Except tensor veli palatini ) Pharynx ( Except stylopharyngeus ) Larynx ( Except cricothyroid ) Supplies the SCM muscle & trapezius muscle CN 11 Accessory Nerve

47. Trapezius Ask the patient to shrug their shoulders and feel the bulk of the trapezius muscles and attempt to push the shoulders down. CN XI Shrug your shoulder, push up against my hand CN 11 Accessory Nerve

48. Sternocleidomastoid Ask the patient to turn their head against resistance and feel the bulk of the sternomastoids. Feel for the sternomastoid on the side opposite to the turned head. There will be weakness on turning the head away from the side of a muscle whose strength is impaired. (Optional)Test neck flexors if suspect myasthenia gravis, MND- “ put chin on chest, I’ll put my hand onto your forehead, push up against my hand” CN XI Turn your head against my hand CN 11 Accessory Nerve

49. Thank You