Cranial nerve examination

detailed examination of cranial nerves

1. EXAMINATION OF Cranial Nerves DR AAMIR HELA PG FIRST YEAR

2. Cranial nerves

3. CN I: OLFACTORY Function: smell Origin: olfactory receptor nerve cells Clinical test for damage: Occlude one nostril, close eyes, and determine whether a person can smell something aromatic (non anoxious ) like coffee, lemon, garlic etc

4. CN II: OPTIC Function: vision ORIGIN: back of eyeball Clinical tests visual acuity visual fields Color vision fundoscopy

5. . VISUAL ACUITY Far vision ( snellens chart) chart is placed at 6 meters and patient is asked to read it Near vision (Jaegers chart) COLOR VISION ishihara chart

6. VISUAL FIELD Confrontation test : ask the pt to look into ur eyes while u place ur index finger just outside the outer limit of temporal field. Test both eyes separately and both temporal and nasal fields one by one. Goldman perimetery : FUNDOSCOPY Look for blood vessels, look at optic disc- clear or blurred

7. CNIII: OCULOMOTOR Origin: ant surface of midbrain Function: eye movements, opening of eyelid, constriction of pupil, focusing, proprioception Clinical tests for injury: Pupil constriction- shape and equality; Light reflex; Accomodation reflex eye tracking Elevate the upper eyelid

8. CNIV: TROCHLEAR Origin: ant surface of midbrain Function: eye movements and proprioception Clinical test for injury: ability to rotate eye downward and inwards. Effects of damage – double vision, patient tilts head toward affected side

9. CN V: TRIGEMINAL Origin : ant surface of pons Function : sensory supply to ophthalmic, maxillary and mandibular regions. Motor innervation to masseter and temporalis muscle. Clinical test for injury: sense of touch, pain, and temperature in v1, v2 and v3 areas; clench teeth; move mandible side to side corneal reflex; Jaw jerk Effects of damage : loss of sensation and impaired chewing. Deviation of jaw towards same side TIC DOULOUREUX: paroxysmal attacks of excruciating pain due to inflammation of nerve

10. CN VI: ABDUCENT Origin: pons Function: Eye movements Clinical test: lateral eye movement Effects of damage: inability to rotate eye laterally; at rest – eye rotates medially because of action of antagonistic muscles .

11. CN VII: FACIAL NERVE Origin : pons Function : facial expression; sense of taste ant 2/3 Clinical test: Facial symmetry Nasolabial folds Ask the pt to shut the eyes tightly Ask the pt to look up and wrinkle the forehead. Ask the pt to show up their teeth Ask the pt to blow out cheeks whistle Effects of damage : inability to control facial muscles; distorted sense of taste

12. CN VIII: VESTIBULOCOCHLEAR Origin: pons Function: hearing and equilibrium Clinical tests: test hearing ( Rinnes test, webers test), balance, vertigo, nystagmus , and ability to walk a straight line Effects of damage: deafness, dizziness, nausea, loss of balance, and nystagmus

13. CN IX: GLOSSOPHARANGEAL Origin: Medulla Oblongata Function: swallowing, salivation, gagging; touch, pressure, taste, and pain sensations from tongue, pharynx, and outer ear Clinical tests: gag reflex, swallowing, and coughing Effects of damage: difficulty swallowing

14. CN X: VAGUS Origin: Medulla oblongata Function: swallowing; taste; speech; respiratory, CV, and GI regulation; sensations of hunger, fullness, and intestinal discomfort Clinical tests: test with cranial nerve IX Effects of damage: hoarseness or loss of voice; impaired swallowing and GI motility

15. CN XI: ACCESSORY Origin: Medulla oblongata Function: swallowing; head, neck, and shoulder movements Clinical tests: rotate head and shrug shoulders against resistance Effects of damage: impaired movement of head, neck, and shoulders; paralysis of sternocleidomastoid

16. CN XII: HYPOGLOSSAL Origin: medulla oblongata Function: tongue movements of speech, food manipulation, and swallowing Clinical test: tongue function Effects of damage: difficulty in speech and swallowing; atrophy of tongue; inability to stick out (protrude) tongue

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