0:00 Hello, in this video, we're going to talk about the clinical anatomy of the 0:08 nasal cavity 0:09 focusing on the sinuses. 0:11 Let's begin by cutting a cross section or sagittal section of the nose and look 0:16 at 0:17 the general structure and revise the anatomy. 0:20 Here is the nasal cavity. 0:21 The nasal cavity is bordered inferiorly by the palate, which consists of a hard 0:27 bony 0:27 palate, anteriorly, and at the back, the soft palate, which contains no bone. 0:34 Of course, you have the oral cavity here and the tongue here. 0:38 The epiglottis is a gateway to the trachea, which connects the lungs. 0:42 The esophagus is the root to the stomach. 0:45 The epiglottis closes when we swallow. 0:49 The throat, I guess we can call the pharynx, and it can be divided into three 0:54 parts. 0:55 The very top is the nasopharynx, which is in line with the nasal cavity. 0:59 The middle is the oropharynx, which is in line with the oral cavity. 1:03 And the bottom is the laryngopharynx, where we have the larynx, essentially. 1:08 Your brain sits in this cavity here at the top, surrounded by bone. 1:13 There's a small hole in the front of our skull, you can say. 1:18 And this is actually a sinus, and this is called the frontal sinus, sitting at 1:22 the posterior 1:23 superior aspect of the nasal cavity, is another sinus called the sphenoid sinus 1:30 . 1:30 Of course, we have actually more sinuses than this, but it's good to know these 1:33 two for now. 1:35 There are other important structures within and surrounding the nasal cavity. 1:39 Let's take a closer look again. 1:41 So here, again, we have the nasopharynx, your hard palate and your soft palate. 1:46 At the back of the nasal cavity, situated really within the nasopharynx, is a 1:51 small opening 1:51 where the eustachian tube, also known as the ferringo tympanic tube, drains 1:59 into. 2:00 This tube literally connects your middle ear to the nasal cavity. 2:04 So if we were to draw the inner and middle ear quickly, this is your middle ear 2:10 where 2:10 you can find your auditory ossicles, the smallest bones in your body. 2:15 And this is the eustachian tube, also known as the ferringo tympanic tube. 2:19 The clinical significance of this is that if you have an upper respiratory 2:24 tract infection, 2:26 this can subsequently cause a middle ear infection because there's this tube 2:29 and it's 2:30 a gateway to the middle ear. 2:32 On each side of the nasal cavity, we also have these things called turbinates, 2:36 which 2:36 are also known as a nasal concae, or a conca for one. 2:41 There is the inferior conca, middle conca, and superior conca. 2:46 The function of the conca, concae, are to help warm and moisturise air that is 2:52 flowing 2:53 through the nose. 2:55 Now behind each respected concae, you have the nasal meatus. 3:01 Some of the sinuses drain into the meatus. 3:05 This really tells us that the sinuses and the nasal cavity are joined together 3:10 as well. 3:11 So for example, the sphenoid sinus drains into the superior meatus behind the 3:16 superior conca. 3:17 The frontal sinus drains into the middle meatus. 3:21 We can't look at the other sinuses from this angle because it's too hard. 3:26 Now you can say the nasal cavity has two segments. 3:30 It has the respiratory segment, which allows air to enter oxygen, and also air 3:36 to go out, 3:37 so carbon dioxide. 3:39 Then the nasal cavity also has an olfactory segment, which is the area which 3:44 allows for 3:45 smell essentially. 3:46 The olfactory segment is lined with a specialised cell type of pseudo strat 3:51 ified columnar epithelium, 3:54 and these guys contain receptors for the sense of smell. 3:58 This segment is located in and beneath the mucosa of the roof of each nasal 4:03 cavity. 4:04 These receptors will make up the olfactory nerve, which is a cranial nerve 4:08 number one, 4:09 and this will be carried back into the brain where smell is perceived. 4:13 Finally, it's important to mention the pouch here, which is the cella torquica, 4:19 which translates 4:20 to the Turkish seat, or Turkish saddle. 4:24 And this is essentially the pituitary fossa, where the pituitary gland sits. 4:28 Of course, the gland doesn't actually sit on it, but it's rather protected or 4:33 encased 4:33 by it. 4:35 Sinitis, also known as carisa, is irritation and inflammation of the mucosa 4:40 membranes 4:41 in the nose. 4:42 Because the nose and sinuses are joined as we have learned, rhinitis can lead 4:47 to sinusitis, 4:48 which is inflammation of the sinuses. 4:53 Let's recap again the anatomy. 4:55 Here is a superior conquer, middle conquer, inferior conquer, and behind each 4:59 conquer 5:00 you have the meatus. 5:02 So here you have the superior meatus, middle meatus, and inferior meatus. 5:06 Here is your sphenoid sinus and frontal sinus. 5:11 This is your nasopharynx, and remember the pharynxotempanic tube drains here 5:15 from the 5:16 middle ear. 5:18 Now this is one angle of looking inside the nasal cavity, but let us cut a cor 5:23 onal section 5:24 and look at the nasal cavity and sinuses from the front. 5:28 To orientate ourselves, this here is the orbit where the eyeball sits, and here 5:33 is our teeth. 5:35 This is your superior conquer, behind it the superior meatus. 5:39 This is your middle conquer, behind it the middle meatus, inferior conquer, 5:43 behind it 5:44 the inferior meatus. 5:47 Below the orbit and lateral to the nasal cavity are your maxillary sinus. 5:55 The maxillary sinus, like the frontal sinus, drains into the middle meatus. 6:03 Here are your frontal sinus which, as we talked about earlier, sits essentially 6:07 above the orbit, 6:08 and they also drain into the middle meatus. 6:12 The ethmoid sinus is the fourth sinus we will talk about, and sits medial to 6:18 the orbit. 6:19 The ethmoid sinus drains into the superior and middle meatus. 6:26 Sinusitis, or should we call rhino sinusitis, is inflammation of the sinuses. 6:31 A feature of someone with sinusitis is essentially redness or erythema around 6:36 where the sinuses 6:37 lie, and so the frontal and maxillary sinus may appear red and irritated. 6:42 The pathophysiology of sinusitis, as we have learned, can be secondary to rhin 6:46 itis. 6:47 Rhinitis may spread to the sinuses, producing swelling and inflammation of the 6:53 sinus mucosa. 6:56 Let's talk about complications of sinusitis, so ethmoid sinusitis is a 7:01 particular concern. 7:03 Ethmoid sinus infection may break the fragile medial wall of the orbit, 7:08 allowing infection 7:09 to spread to the eye, which can cause blindness or even optic neuritis. 7:15 Similarly, frontal sinusitis can also cause some complications. 7:19 This is shared with any sinusitis, but it can cause osteomyelitis. 7:26 For the frontal sinus, if you have infection here, the infection may or can 7:31 invade the 7:32 brain, causing meningitis and even form an abscess in absolutely worst case 7:39 scenarios. 7:40 Of course, these complications are rare, but it is good to know them 7:43 nonetheless.
