Running Time: 39 min
Review the body planes and terminology related to the head and neck, the oral complex, and the teeth. Identify, locate and relate the gross anatomical structures of the head and neck to include the bones of the skull Review the head and neck musculature Discuss the trigeminal nerve Identify the anatomic features of the extraoral and intraoral structures Release: 9/26/2014 | Expires: 9/26/2017
Release Date: September 30, 2014Subtitle:
My name is Karima Bapoo-Mohamed. I’m a dental hygienist from Edmonton, Alberta, Canada. I have my clinical practice there for about two decades. And over that time I’m also the associate clinical professor at the University of Alberta, where I graduated from. So what I’m here to share with you is really my practical, clinical experience and knowledge, as well as many experiences from international presentations and lectures worldwide on various dental hygiene implant topics. Welcome to the module on orofacial anatomy. Today’s learning objectives are going to start with a quick review on the body planes and terminology. We’re going to spend the majority of our time on actually locating and relating the growth anatomical structures of the head and neck. The head is a unique structure in our body because it has to be strong enough to protect vital organs, like the brain and the sensory organs, from mechanical pressure. However, it has to be light enough for the neck to support it. So what are some of the key structural elements about the head and neck, is what we’re going to discuss in the osteology of the skull. We’re going to spend some time in this module on the muscles the head and neck, followed by the trigeminal nerve of the head and neck area. And we’ll finish off this module with the extraoral, intraoral structures. So moving on with our first objective of the module, we’re going to refresh our memories on some of the anatomical directional terms. As we know, anterior, posterior are synergistically meaning front and back. Distal always implies to something away from the origin. Or in our case, it’s usually the midsagittal line. Proximal is something that’s close to the midsagittal line. Dorsal always refers to the upper surface. For example the dorsal surface of the tongue is the upper surface of the tongue, compared to the ventral surface. Superior and inferior are self-explanatory terms. And then there’s the lateral and medial. Lateral always relating to the external aspect. So for example, they ear is lateral to the eye, because it’s external from the midline to the eye. Let’s review the three popular body planes for our head and neck anatomy. The sagittal always implies to the midline, which divides the body basically to the left on the right zones. The frontal plane, or the coronal plane, actually slices the body into the front and the back area. And then the third plane, of course, is the transverse, or the horizontal plane, which actually dissects the body in the upper and lower areas. These plane, of course, become very critical in our CBCT analysis of radiograph. I would now like to move over to our second objective of the module. And that’s really talking about the osteology of the skull. There are 22 bones in the head and neck area. And as we mentioned earlier, it’s a vital role of supporting and protecting some organs, especially the brain. We also want it to serve as a purpose for attaching muscle to this area. And it has to be lightweight enough for the neck to actually be able to support it. So with all of these characteristics and features that are required, let’s take an analysis of these 22 cranial facial bones. So starting with the 22 cranial and facial bones, I’m going to begin with the eight cranial bones. The frontal bone is, of course, of most visual value to us, occupying the forehead area of the body. And as we can see, that it does form part of the skull as well as the eyes. And the roof of the nasal cavities is also occupied by the frontal bone. What’s neat about this bone is it does have the orbits, the roof part of the orbits, are also part of the frontal bone. This is actually showing an image of an 18th-century skull that was ruptured with a sword in the frontal bone area. So it has to be very strong to support the cerebral mass that housing in the frontal bone area. The second critical bone of the cranial facial bones is the parietal bone. And that’s the dome shaped bone, actually it’s a curved plate. And it has four borders around it. This bone is the one that actually bulges on the side, and really provides the roof to the cranium. The other bone is, of course, the basal bone at the skull called the occipital bone. We’re all familiar with this bone in that it is housing the foramen magnum. That is a key landmark for this area, allowing the necessary nerves that connect the spinal cord to the brain. Moving on to the temporal bone, which is actually the sides of the bone. And it’s actually called temporal at the temple area of your bone. The important features with this bone is it does have the mastoid processes, the styloid, the zygomatic arches, as well as the glenoid fossa. And the articular eminence is actually a large part of it, as well, because that’s the feature that’s also holding the auditory canal in place as well. So it’s an important bone because it is supporting the seven cranial nerves that also pass through the bone. The sphenoid bone is actually a Greek word for wedge-like. And as you can see from the image on the bottom, it does look like a bat with its wings extended. And it is this pink colored bone. And it is pretty much wedged right in front of the temporal bone and actually behind the frontal bone. And it serves an important function because it is forming the back part of the nose. It’s also the base of the cranium. And it is also the floor for the orbits of the eye as well. The ethmoid bone is of course very cancellous looking. You can see it’s very spongy, got lots of holes in it. And this is by design, because this is, again, supporting the ethmoidal cells which are related to the olfactory senses of the body. What’s important about this bone is if you have a patient in the chair who has had a recent motor vehicle accident, this is a bone that actually fractures very easily by any trauma to the face. And the neat thing with this is if it fractures along the cribriform plate, which is this little divider right here, it can actually wedge itself into the cerebral fluid and actually break the body brain barrier. So really important to investigate for any breakages around this area if you have a patient with a motor vehicle accident. So that was, very quickly, a review of the cranial bones. I’d like to now move on to the facial bones. There are 14 facial bones. And we’re just going to discuss a few key ones for our purposes today. I am starting with the maxillae, which is, of course, the upper palette of the bone. It is actually two halves that are fused together. The neat thing with this, the key features about the maxillae, is the nasal processes right here. And they actually form the side of the nose. So as this slide describes, it goes upward and medially, forming the side part of the nose. And it’s also an important one because it sutures in the midline, as well. And maxilla holds 10 deciduous teeth and, of course, 16 permanent teeth. As you can see, what we call the palate of the mouth is actually formed by two palatine bone which are L shaped. And they actually fuse in the midline there. And these are horizontal plates which look like the opening up the incisive foramen or the nasal palatine [? foramen. ?] The zygomatic bone, of course, is on the lateral side. And it’s gained an interesting term. “Zygoma” in Greek actually means yoke, which is like a wooden cross piece. This is this cross piece that they used to hold two animals together when you pull a cart. And this is very appropriate for the zygomatic. Because as we can see, it is the one that’s bridging together a few bones, namely the frontal bone, the temporal bone, as well as the maxilla. The mandible, of course, a lot of us like live here in the mouth, is the only movable bone in the whole head and neck region. And its function is to really give shape to the lower portions of the face. It’s also connecting the skull via the temporal mandibular joint, via the condyles. So let’s investigate the mandible a little closely. And here’s a picture showing the two condyles, which is the coronoid processes, as well as the mandibular notch in the middle of the two coronoid processes. We have the mental foramen as well as the mental protuberance, right in the anterior of the chin part of the– and some people have it more prominent than the other. What’s important function, or a landmark about the mandible is, of course, it’s housing the inferior alveolar nerve bundle. The ramus is the ascending limb of the mandible. And that’s a critical feature to know for our local anesthetic injections, especially the inferior alveolar nerve. This slide is again showing different processes. I want to highlight the two condyles that we have the right at the edges here. One would be right along the TMJ area. And of course, we have the external oblique line as well. This slide is also showing the mental foramen right here, which is an exit point for the mental nerve. Again, an important landmark for our local anesthetic. So what is the clinical relevance of this whole mandibular alveolar processes. Well, the important thing is when you have a patient that is edentulous, comparing the two radiographs, you can see the height of the alveolar bone is reduced from there all the way. It’s almost exposing the superior border of the inferior alveolar nerve right there. So when you have this kind of a bone loss, it can be excruciatingly painful for the patient because the nerve bundle is very superficial intraorally. And the other feature about the mandible is a lot of times, it will fracture. And when it does it can be bilateral. So really investigate the radiograph carefully when you have any kind of trauma or fracture to this area. OK, we’ll move on to the muscles of the head and neck area next. And just a quick review of the muscles. We all remember this from school. There’s two ends to the voluntary muscle. There is the origin and the insertion point. And usually muscles work in antagonistical ways. So we have muscle that contract. But for a muscle to contract somewhere, something has to be extended somewhere else. So just a quick review. There are lots of muscles that attach to the bones, the osteology of the skull. But there are some muscles that also attach the skin. And that’s where we get a lot of our facial expressions from. So moving on to the muscles of mastication. There are four paired muscles, the primary ones being the masseter, the temporal, and of course, the internal and external pterygoid. And really the key functions of the masseter muscles is to open and close the jaw. What’s unique about it, too, is it allows the mandible to make protrusive and retrusive movements as well. And I think what’s really phenomenal is the muscles of mastication allow the mandible to move sideways, as well, from the left to the right. So let’s begin with the masseter muscle, as we know it’s located right along the cheekbone area. It is one of the largest muscle, and actually it’s very superficial, as well. What’s neat about this muscle is it will help elevate the mandible. And patients in the chair who, when you’re doing your extraoral exam, feel like they have a very strong masseter muscle are probably bruxers or clenchers or grinders. And so it becomes very important. So long as the muscle’s soft and it’s asymptomatic for the patient, it’s probably a very natural occurrence. But the masseter is very easy one to spot on our extraoral exams. The only downside with a very prominent masseter muscle is that you could have some enlargements that are maybe neoplasms of benign or malignant nature. And it’s likely that you might miss it. So very important when you are testing for a very hypertrophic masseter muscle to really be cognizant of any neoplasms that may exist there. Let’s look at the temporalis muscle. This is, of course, attaching to the temporal bone. And it is a fan shaped muscle which is bilaterally located on either side. Again, the main function is to raise or elevate the lower jaw. The pterygoid muscle, of course, the medial pterygoid muscle, is the one that helps with mastication. Of course, helps with the elevation of the mandible. I wanted to move on to the lateral pterygoid muscle. Now this is interesting because this is the only muscle that helps lower the mandible. All the other muscles of mastication that we talked about help lift the mandible. This is the only one that’ll lower the jaw. So it’s an important muscle for depression of the mandible. The other depressor muscles are, of course, the mylohyoid. And those are located right there on the floor of the mandible. And they help primarily with the opening of the jaw. Facial expression muscles, there are a number of them. And they are really important ones. There are eight paired muscles that give us the facial expressions of the smile and the frown and so on. And we won’t discuss all of these, but I do want to talk about some key ones, starting with the buccinator. I know, in school we used to call it the kissing muscle. But it’s actually called the trumpet muscle anatomically, because this is the one that helps or gives power and pressure in blowing instruments. And it’s helpful in the facial expressions. But it’s also helpful in the chewing and masticatory function the body, as well. It actually helps keep the food in the mouth and help push it to the back. It’s actually in close proximity to your masseter muscles. So again, it overlaps with the masseter, which is going in a different direction. As we know about muscles, their strength is really dependent on the number of fibers and how densely packed the fibers are. So some muscles may be more exaggerated than the others. So that was a quick review of the muscles. We’re now going to move on to the nervous system. And the key nerve is the fifth cranial nerve, the trigeminal nerve, which goes through the head and neck area. Let’s explore the three branches of this cranial nerve, the ophthalmic branch, the maxillary branch, and the mandibular branch. And these are them right there, that we are really pertinent to us in dentistry. This is again showing an animation of the maxillary branch of the trigeminal nerve. And you can see it does divide into individual branches that innervate the whole maxillary dentition there. This is really important for infiltration injections that we do and understanding how very diverse the network the vessels are in here. This is again showing the maxillary nerve in a different viewpoint, where you can actually see the branches. It’s really cool on a human cadaver. And how it divides. And it’s actually a [? sixth ?] trunk of the branch, as well, that is segueing into it. The mandibular branch of the trigeminal is an important one because this is the inferior dental plexus of the mandibular branch. This is where we live for our intraoral injections for the IA block that we always give. And it has thousands and thousands of axons in these cell bodies. And they come from the Gasserian ganglion. And these are really important nerves to really be familiar with. As you can see, this is the ascending superior border of the internal alveolar nerve. And it’s a thick trunk of nerves. If you are able to isolate this nerve, you’re getting a nerve block all the way to the mental foramen area and freezing the posterior part. This is an important enactment of the mental nerve in the exit point from the mental foramen on the lingual aspect of the mandible. So we talked about the local anesthetic considerations. What becomes important is the location of this, and then our insertion site for the injections in this area. As you can see, here is the ascending limb off the inferior alveolar nerve. And this is what we’re trying to isolate when we are placing our injection. And catching the lingual nerve on our way to during insertion. This picture actually shows it maybe a little better, as to the three branches. And one thing we should mention about local anesthetic is we know is that it depends on– it’s very pH-sensitive. And so if you have a patient who has an abscess or a lot of localized inflammation, the pH in that mouth is going to be a lot more acidic, which makes the nerve fibers very slow in the diffusion process of the local anesthetic. So that, coupled with the patient’s really heightened pain sense of awareness, everything’s so painful that this would be a good, as you know, local anesthetic consideration for nerve. So it’s not so much that you’re not isolating the nerve, necessarily. But it’s perhaps that the inflammation and the pH of tissues is interfering with the diffusion of the local anesthetic. OK. And we will move on to the anatomic features of extraoral and intraoral structures as last key objective. Of course, we want to familiarize ourselves and our terms with the gingiva, which is, of course, the 3/4 of the alveolar process around this area by the teeth. The neck of the teeth is a good way of describing the gingiva. It’s about 0.5 millimeters wide. And below the free gingiva is the attached gingiva. And, of course, below that is the alveolar mucosa. So when we’re doing our intraoral soft tissue anatomy, these are the three key features that we should be watching out for. There’s, of course, the vestibules. And there are mucous membrane vestibules in the palate. The two spaces, one is the facial aspect of the teeth, but the internal structures of the cheek and the lip area. And the other one is the lingual aspect of the vestibule on the mandibular teeth and the tongue is the second vestibule. So that’s another important soft tissue anatomical structure. The alveolar processes, we alluded to that earlier. And that’s the bone that is present between the teeth into the jaw bone area there. The residual ridges usually refer to the bone that is left behind. The bone is there and stimulated because of the teeth that are there. And as soon as you lose a tooth, you don’t use it, you lose it. The bone has no reason to live there. So what happens over time is it will just die away. It’s just like getting a cast in your hand. And for six weeks, you have a cast, for example, in your hand or your arm. You take a cast out, and the bone actually shrinks. You can physically see the discrepancy between the two arms. And that’s actually residual ridging, or bone loss, based on not being used or excited. So the bone loves to be stimulated, but not aggravated. And when you don’t have enough stimulation, it will just die on you. And so that’s what’s referred to as the residual ridge or the alveolar ridge. This becomes important as we showed in the earlier slide because the bone is there also protecting this wonderful nerve bundle. And we can’t have too much bone loss because it’s going to expose the fragile nerve endings there. All right, the other area we should also be aware of for the soft tissue anatomy of the mouth is the maxillary tuberosity, which is actually behind the wisdom tooth area. And it does ascend into the condylar area there. So that’s that zone showing on the image there. The hamular notch is a deep depression, which is located posterior to the maxillary tuberosity. And the palate, as we know, has the hard palate and the soft palate. Let me move on to the next slide, and that might describe it a little better. As we can see, the hard palate has the incisive papilla, which is the opening of the inside of the foramen and the nerve bundles coming through there. We have the rugae, which is this insulated, irregular ridges on either side of palate. This is a midpalatine suture that we’re showing right cutting through the left and the right areas there. And of course, we have the palatine raphe, as well. This picture also shows the demarcation point between the hard palate and the soft palate. And that’s that line right there. And that’s called the vibrating line. And it is easy to actually see that abrupt transition between the hard palate the soft palate there. The clinical significance of this is the dentures or dentist fabricating dentures for the patient, they want to limit it right to the posterior borders of this vibrating line the denture, so we don’t want to go beyond that. The palatine fovea is a depression area. There are two groupings. These are actually just minor salivary glands. And sometimes you’ll see them isolated quite easily. The other soft tissue area is the frenum. We have the labial, the buccal, and the lingual frenum. And this is just showing the maxillary frenum right there. The labial frenum is again that narrow fold of the oral mucosa. And it is a good demarcation point of the midline. However, it’s not always on the midline, so we can’t really use that as a guide for midline because people can have off-centric frenums, as well. And, of course, there’s two buccal frenums on the buccal fold area on each side of the arch. And they’re usually located around the premolar area. And then, of course, we have the lingual frenum, which is on the underside of the tongue and only visible when you raise the tongue. Let’s talk about the occlusal plane. So we’ve talked about the skull, and the bones, and the muscles, and the nerves. And now I want to talk about how do these jaw bones actually come together? And this is an important feature– is the occlusal plane. This plane is really the contact between the top and the bottom teeth and how the mandible and the maxilla relate to each other. This will project posteriorly– intersect with the mandible in the two points, and they’re actually both the points in the arch there too. So they’re a good guide. The occlusal plane provides a good guide in determining whether the occlusion is normal or if there are some issues with the occlusion. And especially if you’re fabricating any artificial prosthesis, you want to know where the occlusal plane of the patient is. The other thing with the occlusal plane being abnormal is it will probably have some TMJ relationships as well. So if there is some symptomatic TMD going on, check the occlusal plane for a good reference and a guide. All right. Let’s talk about the sulcuses. These change with the rise and fall, of course, with the facial expressions, and we’re here talking about the labial, the buccal, lingual, and the maxillary sulcus. And really, these are located on the sides of the alveolar ridge, between those various locations. So the labial sulcus is between the alveolar ridge and the labial and the buccal frenum, and the buccal sulcus is, of course, between the alveolar ridge and the buccal aspect of it. Same thing with the lingual and the maxillary sulcus. Now, I guess what’s important to remember is these will change in depth, and size, and dimension as the face moves and changes. The mandibular buccal shelf actually is located at the base of the alveolar ridge in the bicuspid or premolar and the molar regions. And then you have this buccal shelf that’s barely visible. So the clinical significance of this is when you have an alveolar ridge that’s really large and well defined, the buccal shelf is not very easy to observe. Mental foramen– we showed pictures of the mental foramen earlier as the exit point for the mental nerve bundle, and it’s really a fairly large, prominent opening in the mandible, located slightly below the root tips of the first and the second premolar teeth. And sometimes, I’ve noticed over the X-rays that instead of just coming up and looping forward and backwards, it’ll come up medially and then go up [? coronally. ?] And so it’s very important, when isolating that nerve bundle, for example, for your mental nerve blocks that it may not be exactly by the first premolar. And sometimes, the opening may be more closer to the first and the second premolar. What’s important about this is excessive pressure on the mental foramen, of course, can cause freezing, or paresthesia, or discomfort for a lot of patients. So again, fabricating any kind of artificial removable or permanent prosthesis, we want to really be cognizant of the opening and the location of our mental foramen. We spoke about the floor of the mouth earlier and how the mylohyoid muscles are really important in actually helping us with the depression of the jaw, but that’s just showing actually the lingual frenum on the underside, or the ventral aspect, of the tongue. And the depth of this floor, of course, changes again with the contraction and extension of the tongue muscles. So let’s go there. Let’s talk about the tongue and how the muscles of the tongue work. And what are the functions of the tongue? Well, it is a large musculature organ, and it has very specialized cells, very unique to this organ of the mouth. Of course, the brain will intercept with these muscle very acutely to detect taste sensation, and that is from the chemical receptors that are present on there. The tongue is also a very important function for speaking and chewing food, of course. And what’s really important is examining the tongue on both the dorsal and the lingual surfaces, as well as the ventral surfaces because you could have oral pathology related to the tongue area there too. Of significance too is, again, when we’re fabricating prosthesis that the tongue is such a strong muscle, it can actually reject or remove a lot of the denture that aren’t retain very accurately in there– so very important to watch that the tongue is in harmony with all these other structures that are in the mouth. And of course, we again talked about the functions– the big key thing is when we are having an intraoral oral exam of the tongue, and you take your gauze, and you’re taking a good look at the dorsal surface of the tongue, you are actually looking for the three types of the papillae that exist there– the fungiform, the foliate, and the circumvallate. Circumvallate are located more on the posterior aspects. And of course, you just want to look for the integrity of these papillae because they are so critical in the taste sensation of the mouth. They also help manipulate the food, as we talked about. They actually help push the food back into the glottis and the epiglottis area as well. And of course, the saliva becomes very important lubricant for the time tongue to perform the functions that it does. And there are the tongue muscles. There are actually two types of muscles that exist in here, the intrinsic and extrinsic muscles. And they actually originate, pretty much, from the hyoid bone and the styloid processes of the temporal bone. And they’re really important because they work synergistically to provide all the functions that we’ve talked about. Moving on to the salivary glands, this is again a very important aspect of the head and neck anatomy. As we’re doing our external examinations, we are checking for the parotid gland. Now, the parotid gland location is actually very similar, or very close to, the masseter muscle that we talked about earlier. So again, if the parotid gland is very prominent, you could very much confuse it with a very hypertrophic masseter muscle as well because the location of it is very similar. The other salivary gland we want to point out is the submandibular gland. It is bilaterally found on the mandible area on either side of the midline, and it’s usually around the mylohyoid muscle, on the posterior edges there. The sublingual gland is more in the [? mental ?] area. And we’re also just checking for any abnormalities doing our extraoral exam, so it’s important to know where these glands are located and what are we looking for when we’re doing our extraoral exam. So anything that’s abnormal or feels like a bump or doesn’t– or is symptomatic for the patient merits a close examination for some gland duct areas. And there are numerous minor salivary glands, of course. They’re located in many places on the interior of the mouth, especially the palate of the mouth that we’d talked about. And so it’s good to be aware of all those salivary gland location areas. We briefly talked about the TMJ, and I just want to say that you are also checking, as part of your extraoral exam, the articulation of the TMJ and how the condylar processes are relating to the mandible and that fossa– and the glenoid fossa. And of course, this is in the temporal bone area of the skull. And so very important to do that bilateral– looking out for pain. And aside from pain, I also look at deviations. Does it deviant upon closing or upon opening? Because that again gives us a reference to the occlusal plane of this patient’s mouth. So what are some of the common causes for TMJ pain? It is symptomatic. If the TMJ feels OK, it opens and closes fine, but the patient is wincing a little bit– again, you’re asking, does that hurt? So only sometimes, or sometimes you’ll hear a clicking sound, or it doesn’t happen all the time, but when I try and bite into a burger, yeah, I can certainly feel a sharp pain in my jaw. And really, that has to be something to do with either the muscle attachments there or the nerve endings there. So it can range. Sometimes, the pain is so bad– I had a patient in the chair where they had very limited range of motion. And she was at a point where she’s just– literally all her ingestion was through a straw. So anything that was liquid in form was the only thing she could actually ingest because she didn’t have range of motion in the jaw. So based on that, I think this merits a huge examination in our chairs, and I know we’re running late sometimes and anxious to get to the next patient, but take those four or five minutes initially to do a very comprehensive external and internal examination, especially the TMJ. Sometimes, the TMJ pain can also be related to some systemic diseases, and we have a separate module dedicated to that important topic of systemic diseases and oral links. So again, the signs and symptoms. There could be some sounding– this is just recapping the TMJ disorder dysfunction. There could be some clicking, grinding sounds the patient may complain about. There could be some limited range of motion. Sometimes, a patient may have ear discomfort as well, and sometimes it can be related to some facial pain. Patients who’ve been through some motor vehicle accident or some kind of jaw trauma, of course, would have a lot of TMJ issues as well. Interestingly, headaches– sometimes, people have continual or repeated headaches, and it may not necessarily be due to the headache area, but it’s actually connected to the origin being the TMJ. So really investigate and refer your patient accordingly. Sometimes, a TMJ symptom can also be dizziness, actually. So it could be pain in the TMJ. It could be pain in the jaw area. And sometimes, the teeth and even the basal area of your neck can get painful, all originating from the TMJ. So going back to that patient I was talking about, I did refer her to a TMJ specialist. And she’s not only got restored range of motion, but her pain– she says my neck ache is gone, and she didn’t even realize she had a neck ache. And it was all related to that one area of the TMD– so very important anatomical part of the head and neck, and something we should take a close look and examine on a routine basis for our appointments. So this pretty much recaps our module for orofacial anatomy. We started out with reviewing the terminology and the three critical plains of the body. We then moved on to the osteology of the skull. We discussed some of the key muscles of the head area and, of course, discussed our trigeminal nerve and its indications to local anesthetics. And we finished off the module with some extraoral/intraoral soft tissue anatomy. So with that, I would like to leave you with a story that is very near and dear to me because it’s a story about the cat and tail that was told to me by my dad when I was very young. And you might have heard this story, but it’s about this little kitten that’s playing in the alley, and she’s trying to catch her tail and put it in the mouth. So this old alley cat walks by and says, hey, little kitten, what are you doing? And this little kitten has a real attitude, and she says, well, I have been to cat philosophy school, and what I have learned is happiness is the most important thing for a cat. And the other thing I learned– that it’s located in my tail. So if I catch my tail and capture it in my mouth, I will have happiness forever. So this old cat– you know, very wise– ponders and pauses for a minute and says, well, you know, little kitten, I never went to any cat philosophy school. I’ve just walked these alleys all my life. But what’s interesting, little kitten, is I’ve learned the same two things– that happiness is the most important thing for a cat, and it is, behold, located in our tails. But the only difference, little kitten, is I learned if you go about doing what’s important to you in your life, your tail will always follow you. So my message to you is do what’s important to you in your life. Do those comprehensive extraoral/intraoral exams. And I tell you, in my clinical practice, I’ve saved at least two patients’ lives from doing the comprehensive exam by understanding the oral facial anatomy. So with that, thank you very much for your attention. Live life passionately. Thank you.