[MUSIC] The next part of the extraoral examination includes a cranial nerve examination. We perform this examination if there is a patient that has a significant facial pain component. The gross cranial nerve exam is done with actual ease. The most important part is to remember that there are 12 cranial nerves. So, for olfaction, which is cranial nerve number one, we'll just often ask the patient if they can smell a certain substance, perhaps the hand sanitizer, or if there is some type of solvent that has a very distinct odor. Cranial nerve number two is the optic nerve, and again, we often will perform this by asking the patient to read something on the history that they have brought into the patient. Part of the optic nerve is to also identify the fields of vision, of which case you would ask the patient to look straight, and for demonstration purposes, ask for them to evaluate when they're able to see my fingers in their peripheral vision. Tell me when you can see the fingers. >> Now. >> Beautiful. And. >> Now. >> The cranial nerve number three is your ocular motor nerve, and that nerve often is tested by asking a patient to follow your finger as they hold their head steady. As you're asking them to look at your finger in all of its movements, you're also asking them. You're also checking not only the third cranial nerve, but also the fourth cranial nerve, and the sixth cranial nerve. The fourth cranial nerve being the trochlear nerve, and the sixth cranial nerve being the abducens nerve, which controls the lateral rectus muscle. The lateral rectus allows for lateral visualization, and the trochlear nerve allows for downward and inward movement of the eye. As part of the gross cranial examination, often we will have either a pen light, or if one is not handy, we'll ask the patient to look at the light, and be able to determine whether or not the pupils are reacting to that light. We'll often cover one, followed by covering the other, and making sure that the light is in fact causing the pupil to constrict. For cranial nerve number five, which is most important to the dentist, we will perform this cranial nerve examination in a little bit more detail than some of the others. If we remember, cranial nerve number five is divided grossly into three segments. V1 which is the upper portion of the head, V2 which is the mid portion of the face, and V3 which is the lower portion of the face. All of which go to midline. Sorry about that. So we would like to test cranial nerve number five to light touch to be able to discriminate between a sharp point and a dull point, as well as to be able to discriminate if something is cool, has a cool sensation. So for these purposes, I'm going to use just a standard gauze. And I'll ask the patient, as I place a little bit of the wisp of the gauze in different segments of their face. So I'll first ask them if they can feel this as light touch in all three segments. And can you feel that? >> Yes. >> And then I'll ask them, does it feel equal on both sides? >> Yep. >> In all three segments. >> Yes. >> Good. As part of this examination, I'll also perform a corneal reflex. I'll ask the patient to open up their eyes wide, and I'll just sort of brush, very gently, the cotton in the corneal region, and you'll see a normal twitch. In order to test sharp dull in a patient when we're in the dental office, we've devised a cotton applicator, where we break the cotton applicator and it is a sharp point on one end, and a dull point on the other. Now we will ask the patient if they're able to discriminate sharp from dull. Once again, we'll do that in all three segments of the face, and we'll ask them if the sharpness on the one side feels equal or roughly equal to the sharpness on the other side. The last portion of the patient's examination, we'll be able to discriminate if the patient can tell a cold sensation. And for this, our dental mirrors are very good tools where we can ask the patient, the metal, does that feel cool? And does it feel equally cool on the other side? Once again, we'll use that in three distinct areas. This is a very gross cranial nerve examination. However, if there are deficiencies in that nerve, further testing can be done. So thus far, we've accomplished cranial nerves one through six. For cranial nerve number seven, this is our facial nerve, and this is the nerve that is associated when a patient has a Bell's palsy. This is a relatively easy nerve to test because we ask patients about facial expression. Would you please smile? And would you frown? Wiggle your eyebrows up and down. Can you blow up your cheeks? And also, we'll ask them to close their eyes, to see if we can part their eyes, just slightly. Any facial weakness would be determined by this examination, and would warrant additional evaluation. Cranial nerve number eight is the vestibulocochlear nerve. This actually is a nerve that has two purposes. One is for hearing, the other is for balance. I will not perform a standard balance examination, but it will be obvious, in discussing with a patient if they're off balanced, or upon the general survey of them walking in, if in fact the patient has balance issues. A gross cranial nerve exam for hearing is to ask the patient if you can hear equally in both ears. Now mindful, this is not a very detailed examination. For those purposes a Rene or Webber examination is often performed to determine whether or not there is a sense in neural hearing loss or conductive hearing loss. For today's purposes however, we asked the patient if they could just hear us whisping our fingers together equally on both sides. Cranial nerve number number and cranial nerve number ten are associated with. Well, cranial nerve number nine is associated with both motor and sensory perceptions. In fact, if the patient has some pain or even has a lesion in the back of their tongue, they'll often feel pain into their ear. And this is through cranial nerve number nine. Cranial nerve number nine is also associated with the patients gag reflex. As is cranial never number ten which is referred to as the vagus nerve. So often when we inspect a patient, and I'll show you this when we look intraorally in just a minute. At the patient's back of their throat, we like to see the tonsils and the back of the throat move up together evenly to make sure there are no deficiencies in cranial nerves number nine or cranial nerve number ten. Cranial nerve number 11 is the spinal accessory, and we'll ask the patient to shrug their shoulders. And we'll feel if there's good muscular tone in the patient's shrugging of the shoulders, which is again, associated with the spinal accessory nerve. Lastly is cranial nerve number 12 which is referred to as the hypoglossal nerve. This is the nerve that produces motor to the tongue, so often we'll ask the patient to stick out their tongue. We'll ask to move their tongue right and left, and be able to follow commands in doing so. In patients that have a deficiency in the hypoglossal nerve, when they protrude their tongue, their tongue may move to one side only. Can you pretend to do that for us? >> Sure. >> Right. Which would suggest that one of the nerves on the right side or the left side is working properly, whereas the other side is not.
