0:00 Hello, in this video, we're looking at anatomy of the thorax and we will look 0:11 at fractures 0:12 as well as nerve box, so more from a clinical aspect. 0:15 So here is the anterior view of the thorax. 0:18 This here is known as the superior thoracic aperture and many important 0:22 structures pass 0:23 through here. 0:25 The superior thoracic aperture is a small passage for structures from the thor 0:29 ax to the 0:30 head, neck and upper limbs. 0:33 The boundaries of the superior thoracic aperture is anteriorly the menubium, 0:40 posteriorly the 0:42 vertebra T1, laterally the first pair of ribs and their costal cartlages. 0:49 So that was the superior thoracic aperture. 0:52 Then we have the inferior thoracic aperture. 0:56 The inferior thoracic aperture provides a point to which the diaphragm attaches 1:02 . 1:02 Some important structures pass through the diaphragm, and these are the 1:08 inferior vena 1:09 carbure at T8, the esophagus at T10 and the abdominal aorta at T12. 1:16 The boundaries anteriorly is the Ziffy sternum, anteriorly is the costal cartl 1:22 ages of ribs 1:24 7 to 10, posteriorly is the vertebra T12, and posteriorly is the ribs 11 and 12 1:35 . 1:35 So I hope those made sense. 1:38 So that was the superior thoracic aperture and the inferior thoracic aperture. 1:43 Now let's look at thoracic cage injuries. 1:47 Now the middle ribs are commonly fractured. 1:51 Fractures usually results from blows of crushed injuries. 1:56 So let's look at some types of fractures. 1:59 And these can be things such as a costo-vertebral dislocation here, a trans 2:05 verse rib fracture, 2:07 an oblique rib fracture, an overriding rib fracture. 2:12 So it goes over, conjural fracture within the cartlage, costo-conjural 2:19 separation, the 2:20 separation between the cartlage and the bone, conjural sternal separation, conj 2:28 ural sternal 2:29 separation, so that's sternal involvement, as well as a sternal fracture. 2:37 And this is right in the center of the sternum. 2:41 So those were some types of thoracic cage injuries. 2:45 Now let us look a bit more about what are some arteries, nerves and veins that 2:53 go through 2:54 here and supply these ribs, essentially. 2:59 So here we have the anterior view of the thorax. 3:01 Let's cut through here, cross-section, and look at what important structures we 3:07 can find. 3:08 So here we're looking superiorly on the slice we just cut. 3:13 And here we can find the thoracic aorta, which gives off arteries to supply the 3:20 thoracic 3:20 region, essentially the ribs and stuff. 3:23 So this particular artery here coming off is the posterior intercostal arteries 3:28 . 3:29 So the posterior intercostal artery comes off the thoracic aorta. 3:34 Starting around this area we also have the internal thoracic artery, which is a 3:37 branch 3:38 of the subclavian. 3:40 But essentially the internal thoracic artery gives off the anterior intercostal 3:45 artery. 3:46 So the anterior intercostal artery and the posterior intercostal artery will an 3:51 astomose, 3:52 and these guys will supply the ribs, essentially, as well as the parietal ple 3:57 ura, which sort 3:59 of surrounds the lung. 4:02 So those are the arteries. 4:03 Let's look at the nerves now. 4:05 So the nerves, it comes off the sympathetic chain here. 4:09 We have the dorsal ramai and the ventral ramai. 4:14 And these guys, essentially, form your intercostal nerves. 4:18 And your intercostal nerves are important because this is how we perform a 4:22 nerve block, 4:22 which we'll talk about later. 4:24 Okay, now let's take another cross-section over here. 4:28 And why we're taking cross-section is because we want to see where these inter 4:33 costal nerves, 4:34 arteries, and veins actually pass through in respect to the ribs. 4:38 So here we have one rib, and here we have another second rib below it. 4:44 Now actually there are muscles attaching to the ribs, and these muscles are 4:48 important 4:48 in respiration. 4:50 So let's just look at the muscles. 4:52 The most outside muscle that attaches to the ribs are the external intercostals 4:59 . 5:00 And the second layer of muscle is the internal intercostals. 5:07 And then we have another one called the innermost intercostals. 5:11 Now the nerve artery vein, which make up the neurovascular bundle, are actually 5:18 found below 5:20 each rib, so just under the ribs. 5:23 And so all here, these are all the intercostals, neurovascular bundle. 5:29 And we can remember it as a van, and this is the order we find it in. 5:35 So we have vein right below the rib, then we have the artery, then we have the 5:39 nerve. 5:40 So the nerve is the most unprotected out of the lodge because it's the most 5:46 exposed. 5:47 So again, we have the intercostal vein below the rib, then right after the 5:52 intercostal vein, 5:54 we have the intercostal artery, and then the intercostal nerve. 5:58 And these three are found between the internal intercostal and the innermost 6:06 intercostal. 6:08 So another layer, which is under the innermost intercostal, is the parietal 6:15 layer of the lung, 6:17 and then the other layer is the visceral layer of the lung. 6:21 In between the parietal layer and the visceral layer, we have the glural cavity 6:28 essentially. 6:29 Anyway, it's important to know about the intercostal nerve because the inter 6:35 costal nerve 6:35 is sensory. 6:36 It can sense pain when there's pain involvement, when the ribs are fractured, 6:42 for example. 6:43 And also, it innervates the parietal layer. 6:46 So if we have some pain within the plural cavity, it can cause pain as well. 6:53 So that is why the intercostal nerve is important. 6:57 So going back to the rib fractures, remember all these rib fractures we're 7:00 talking about? 7:01 Well, they are very painful because the intercostal nerves are sending pain 7:07 signals to the brain. 7:09 So that is why in the treatment for rib fractures, we actually block the inter 7:15 costal nerves. 7:16 So rib fractures are very painful due to the expansion of rib cage during 7:21 breathing. 7:22 And so we may require a intercostal nerve block. 7:25 So again, let's go back to that similar diagram. 7:29 We have the ribs here. 7:31 Now, let's just go one step further and look at the most outer layer, which is 7:36 the skin. 7:37 Below the skin is the subcutaneous fat. 7:39 And then below the subcutaneous fat, that can be another muscle layer. 7:43 It can be the serratus anterior, depending on which region of the thorax is 7:51 involved. 7:52 And then essentially, and then you have the muscles of the ribs, which are your 7:56 , remember, 7:57 external intercostal, internal intercostal, and innermost. 8:01 And then between the internal intercostal and innermost intercostal is your 8:05 neurovascular 8:06 bundle. 8:07 So the point of the intercostal nerve block is to essentially put a needle 8:14 around this 8:15 area to essentially block the nerve so that we don't feel pain. 8:21 So it is important to know what order the neurovascular bundle is in. 8:26 And remember, it's van from the bottom of the rib. 8:29 It's vein, artery, nerve. 8:31 And it's important because we don't want to, you know, we don't want to hit the 8:35 artery 8:36 of the vein because then the person can bleed out from within, so we don't want 8:40 that. 8:40 So that is why in the intercostal nerve block, we find the lower margin of the 8:46 rib, of that 8:47 particular rib. 8:49 We find it, we insert the needle inside, that's step one. 8:53 And then just before, you know, when we find the lower margin, then we tilt it 8:57 slightly 8:58 down and that way we will definitely know that we are targeting the nerve most 9:05 likely. 9:06 And then we inject the anesthetic and essentially this way we are blocking that 9:11 nerve, blocking 9:12 the pain now without damaging any structures, damaging the veins or the 9:17 arteries. 9:18 So hope that made sense, the intercostal nerve block. 9:21 And hope you enjoyed this video, thank you for watching.
