Examination of the Cranial Nerves - Explanation

hello I'm doctor rabbit I'd like to examine the nerves around your face and head would that be okay with you yeah at this point I'm making observations of the patient's to see if I can see any abnormality in the cranial nerve distribution this might be something like ptosis strabismus lack of facial expression salivation muscle wasting or facial asymmetry the first cranial nerve is the olfactory which is responsible for the sense of smell have you noticed any problems with your sense of smell no if the patient complains of anosmia or taste abnormalities these can be explored using a smell testing kit the optic nerve is the second cranial nerve the tested components of visual acuity visual fields and panned Oscar be using the ophthalmoscope I will test the security first if the patient wears spectacles then testing is done with the patient wearing them in order to correct any refractive errors I'd like to test your visual acuity can you tell me whether you wear spectacles please no no okay I'd like you to read some print off here could you take us in your hand and cover up the right eye please could you read the top line he moved forward a few steps the house was so dark behind him the world so dim and uncertain in front of him okay can he swap eyes and hands Napoli then he heard us as a sniff felt something warm against his leg he had almost stepped upon the animal he bent down and stroked it's wet coat okay that's great thank you I've just used a specialist chart which is likely to be available in a special clinic if you're doing the testing at the bedside in something like a magazine or a book would suffice if you do find an abnormality of visual acuity then you may choose to use a Snellen chart in order to quantify the defect further I know to test your visual fields could you cover your right eye with your right hand please I'd like you to look and concentrate in the center of my eye I'm going to bring my finger in and when the finger moves I'd like you to say yes yeah yeah when I'm doing this I'm comparing the patient's visual field with my own yeah okay could you swap eyes now please yes yes yes yeah if an abnormality is detected a formal visual assessment by perimetry or central field assessment would be organized well finis Coupee it's best to dim the lights in order to allow the people to dilate and to ask the patient not to look directly at the beam so that the eye stays in a fixed position I'd like to examine the back of your eye using the ophthalmoscope what I'd like you to do please is to look behind me at the clock and focus on the clock and not look straight at the light please notice for doing this I'm using the ophthalmoscope for examining the patient's right eye in my right hand and I'm going to look into his right eye through my right eye first of all I'm going to examine the red reflex I'm now going to move closer to examine the back of the eye I'm looking at the optic disc I'm looking at the vessels I'm now going to scan the rest of the retina I'm not going to move to look in the left I going to swap the up thermoscope into my left hand and I'm going to examine the patient with my left eye looking at his left eye again if you could look into the distance please again check the red reflex and then examine the back of the eye the cranial nerves 3 4 & 6 are usually examined together tested components are the ocular movements under pupilary reactions first I look at the ocular movements I checked at the normal resting position of the eyes and then at the full range of movement alright I'm going to test the movement of your eyes now please what I'd like to do is get you to focus on the tip of my pen I'd like you to follow with your eyes and keep your head still I'd also like you to tell me when you see double at any position okay so if you just follow my pen I'm taking the patient's eye movements to the extremes of horizontal gaze first and then examining vertical gaze at all stages I'm looking to see if there's any nystagmus in any particular position I'm now going to test for the movements of the oblique muscles okay so you didn't see double in any of those positions looking at the individual nerves in turn the abducens innovates the lateral rectus muscles which are responsible for abduction of the eye when the patient has a left sixth nerve palsy the lateral rectus muscle will malfunction when the patient looks horizontally to the left side the left I will not abduct normally patient will complain of double vision and the images will be horizontally displaced the trochlear nerve innervates the superior oblique muscle and it's action is demonstrated by asking the patient to look downwards and inwards with a left fourth nerve palsy there will be a weakness of the left and superior oblique when the patient looks downwards and inwards they will complain of double vision with oblique displacement of images because the double vision occurs on looking towards the right the patient tends to feel that there's a problem with the right eye rather than the left all of the other eye movements involve the ocular motor nerve this nerve also innovates levator palpebrae superioris where weakness will result in ptosis in the full picture of third node palsy the pupil will be dilated and the eye will deviate downwards and outwards can you follow the pen again please as the eyes converge both pupils are seen to constrict the light reflex involves the perception of light by the afferent fibers of the optic nerve with the efferent parasympathetic fibers carried by the third nerve I'm going to shine a light into your eyes I'd like you to look out into the distance please I'm going to test the direct and consensual light reflexes in the direct reflex I shine the light in the right eye and the right pupil constricts I shine the light in the left eye and the left view constricts when testing the consensual light reflex i shine the light in the right eye and the left eye book constricts i shine the light in the left eye and the right people constricts fifth nerve the trigeminal has both sensory and motor components light touch sensation is tested in the ophthalmic maxillary and mandibular divisions I'm now going to test the sensation on your face I'd like you to tell me if it feels the same on each side yeah yeah yeah the corneal reflex involves afferent fibers from the ophthalmic division of the trigeminal nerve and afferent for the facial nerve if incorrectly I touch the insensitive sclera no response occurs when correctly I touch the cornea a bilateral blink responses obtained this test is uncomfortable it can be omitted if sensory impairment is not suspected the motor function of the trigeminal nerve is to innervate the muscles of mastication I'm going to test your jaw muscles now please can you clench your teeth tight keep clenching I can feel the temporalis muscle contracting and again please I can feel the Meseta contracting can you open your jaw now please the pterygoid muscles open the jaw in the midline could you keep it open for me the pterygoid is are strong and I should not be able to overcome this movement can you move your jaw from side to side if the right pterygoid muscle is weak the jaw will deviate to the right and if the left is weak it will deviate to the left the facial nerve innervates the muscles of facial expression and bucks inator I'd like to test your facial muscles now could you raise your eyebrows fully please and we're looking for wrinkling of the forehead due to contraction of the frontalis muscle and this should be symmetrical you now screw your eyes tight together we're testing the orbicularis oculi muscle and I shouldn't be able to open the eyes thank you now can you smile like this please and I'm looking for symmetry of the smile and equal action of the obq Larry's Oris muscle now can you blow out your cheeks this is a function of the Bucks innate in muscle I press gently and see if there's any incontinence of air and escape of air from the mouth thank you the eighth nerve the vestibulocochlear has auditory and balanced functions I'm going to test your hearing I'm going to cover one ear whispered number in the other would you tell me what the number is please 36 no 43 okay if I detect any hearing deficit I would move on to the tuning fork tests I'm going to do some tuning fork tests this is the latest test and you hear that vibrating yeah does it sound loud on one side or the other it's the same on both right that's normal we're now going to do the Renee test can you hear that vibrating yeah please will you tell me when it stops I can't do it and you hear that yep that's a normal Renee test I've now go on to repeat the test on the opposite side both of these tests rely on the fact that normally air conduction is better than bone conduction if the air passages are blocked then air conduction will be reduced and this is conduction deafness if the auditory nerve is affected then both modalities will be reduced and this is sensory neural deafness the bulbar nerves are conveniently examined together now I'm going to test your throat and mouth first of all could you give a loud cough please okay this tests the vagus nerve now I'm going to test for articulation which involves coordination of tongue teeth and lips and requires the facial Vegas and hypoglossal nerves could you say the days of the week Sunday Monday Tuesday Wednesday Thursday Friday Saturday okay what I'd like to do now is to examine the back of your throat could you open your mouth wide for me can you say ah ah and again please ah thank you the soft palate should move upwards essentially to protect the nasal pharynx when the patient swallows if there is palsy the soft palate is pulled to the stronger side the gag reflex is elicited by gently touching the posterior pharyngeal wall on each side and results in a gag response it is uncomfortable and not usually tested in the conscious patient it requires both cranial nerves 9 and 10 for afferent and efferent roles respectively 12th nerve the hypoglossal innovates the motor supply to the tongue I'm going to examine your tongue could you open your mouth for me because you protrude your tongue can you move it from side to side now can you push your tongue against my fingers and you do it on the other side please thank you the accessory nerve innervates the sternomastoid muscles and the upper fibers of the trapezius I'm going to test your neck and shoulders could you shrug your shoulders for me please I'm looking for symmetrical elevation of the shoulders by the trapezius muscles here next go get you to turn your head against my hand and I'm looking here at the sternomastoid muscle if we could do it the other side please could you turn your head against my hand again and again we're looking at the sternomastoid muscle here okay that's what I need to examine thank you you

Channel: University of Leicester

Views: 1,756,401

Keywords: Optic, Visual Acuity, Visual Fields, Fundoscopy, Oculomotor, Trochlear, Abducens, Ocular Movements, Pupillary Reactions, Trigeminal, Sensory function, Motor functions, Facial, Vestibulocochlear, Glossopharyngeal, Vagus, Hypoglossal, Bulbar Nerves, Accessory

Id: vU8-PLsdJ-w

Length: 16min 14sec (974 seconds)

Published: Mon Apr 30 2012