Health Assessment, part 28: Cranial Nerve IX - Glossopharyngeal & Cranial Nerve X - Vagus

Hi. I'm Meris, and in this video, I'm going to be reviewing the type, function, and assessment of cranial nerves 9, glossopharyngeal, and 10, vagus. I'm going to be following along using our health assessment flashcards. These are available on our website, leveluprn.com, if you want to grab a set for yourself. Or if you prefer digital products, you should check out Flashables, which are our digital flashcards available for all of the different flashcards that we have. All right. Let's go ahead and get started.

So first up, we are talking about cranial nerve 9, glossopharyngeal. And although you may not feel like this one tells you what it is, it does. Glosso is a word that refers to the tongue, and pharyngeal refers to the pharynx. So glossopharyngeal is a nerve that has a function associated with the tongue and the pharynx. Now, when we talk about the sensory function of this one, this one is mixed. We have sensory and motor function. The sensory function of cranial nerve 9 is going to be taste on the posterior, the backmost one-third of the tongue. And then the motor function is going to be the gag reflex, pharyngeal muscles, such as those involved in swallowing and producing speech, and the parotid glands function. So you got to remember, taste is just that posterior one-third of the tongue. It is not the entire tongue.

Now, how do we assess this? Well, we don't routinely assess the sensory function when it comes to taste. However, when it comes to assessing the motor function of this nerve, this is one of the things that you have definitely had somebody do to you in a medical setting. Have you open your mouth, stick out your tongue, and say, "Ah," right? You have a structure called the uvula, which hangs in the back of your throat. And so saying ah, actually there's an assessment purpose to it. It is to see if the uvula rises midline on phonation, which is a very fancy way of saying that when I say, "Ah," you should be able to observe that my uvula rises, and it rises midline, meaning it is not rising to the left or to the right. It's going straight up the middle when I phonate, when I make a sound such as ah. So that is how we are going to assess for the motor function of the pharyngeal muscles there.

Now, we can also assess for the gag reflex. This, yet again, is not something that we are doing routinely. This is typically a specialized assessment, maybe in a postoperative care unit when we are trying to see if our patient's gag reflex has returned to allow them to eat and drink. Or if we are talking about somebody who might be experiencing brain death, and there's assessments done on different reflexes to see if there is any kind of a response there. To elicit the gag reflex, the nurse would use a tongue blade and touch the posterior pharyngeal wall. So we're just touching the wall of the pharynx in the posterior, usually on either side with a tongue blade. We are not sticking our fingers in our patient's mouths, right? We use a tongue blade. And then we can also assess the motor function by assessing swallowing ability. This can be by just asking the patient to swallow. This can be by placing your hands on either side here and feeling as they swallow. Or it could be by having them take a sip of water.

All right. So moving on to cranial nerve 10, the vagus nerve. This nerve is a very important nerve, and it's super important when it comes to our parasympathetic response and our rest and digest, all of that good stuff that we love. But this is both a sensory and a motor nerve as well. And the function here, the sensory function is not one that we are able to test and is not one that you are probably even aware of, but the sensory function is that it controls thoracic and abdominal organ sensation. So all of those visceral sensations, the organ sensations are controlled by the vagus nerve. Now, again, vagus nerve also has a role in the gag reflex and the pharyngeal and laryngeal muscles, for instance, those responsible for producing sound and speech and swallowing. So very similar, glossopharyngeal and vagus. They both have very similar intertwined motor components to them.

So how do we evaluate it? We're going to evaluate it with cranial nerve 9, glossopharyngeal, because they have the same function. So when you are evaluating cranial nerve 9, you are also evaluating the motor function of cranial nerve 10. Very, very nice and easy that way. We do, however, have a cool chicken hint here on this card. If you are new to Level Up, then cool chicken hints are our fun and catchy mnemonics ways to remember things. And this one is a little bit long, but it's a good one because it helps you remember all of these functions. When you go to Vegas, like the vagus nerve, you are out drinking, swallowing, and talking with your friends, speech. You may gag, gag reflex, if you get sick from drinking too much. So I'll just say it again without all the little hints there. When you go to Vegas, you are out drinking and talking with your friends. You may gag if you get sick from drinking too much.

All right. So that is it for the review of glossopharyngeal and vagus nerves, cranial nerves 9 and 10. I'm so glad you stayed until the end because I'm going to test your knowledge of some key facts I provided in this video using these quiz questions. What is the sensory function of cranial nerve 9? Taste on the posterior one-third of the tongue. How should the nurse assess a patient's gag reflex? By touching the posterior pharyngeal wall with a tongue blade.

All right. That's it for this video. I really hope you found this review useful. Thanks so much, and happy studying.