Full transcript of “Anatomy Thorax Overview - Ribs, Sternal angle, Pleura and Pneumothorax”. Click a timestamp to open the video at that moment. Need another video? Use the YouTube transcript generator.
0:05 Hello. In this video, we're going to look at uh anatomy of the thorax. So, here I'm drawing the rib cage, the thorax area um from an anterior view. And here at the back is our vertebrae, the thoracic vertebrae. We have 12 in total. So, T1 all the way to T12. And I'm also adding the lumbar one. the lumbar vertebrae number one coming off the thoracic vertebrae 12. So T12 we have the 12th rib which is a floating rib here. Here is our clavicle and scapula. Now the ribs um originate from the vertebrae and connect to the sternum. The ribs actually joining to the sternum
0:51 form cartilage allowing for the expansion of the thorax during respiration. The sternum itself forms three parts. The manubrium of the sternum, the body of the sternum and the zyoid process of the sternum. Drawing the sternum from a side view. Now it is important to appreciate an important landmark which is marked by the sternal angle between the manubrium and the body of the sternum. This surface marking is also referred to as the angle of Louisie. On this side view of the sternum we can see the insertion points of the ribs. Rib one attaches onto the manubrium. Rib two to the sternal angle. rib 3 to six
1:37 to the body of the sternum and here is the um zifist sternal joint and on top here is the clavvicular notch where the clavicle attaches the clavicle and sternum make up the sternocclavicular joint. Now as I said the sternal angle or the angle of Louisie is an important landmark because many uh structures can be found along this angle. So if we were to cut straight along a hor in a horizontal plane along a sternal angle, we will hit and find uh these things such as uh the the joint between thoracic vertebrae 4 and 5. So T45 the
2:24 second rib articulation occurs here. We can find the aotic arch, zygus vein as well. um entering into the heart we have the ligamentum arteriosis we have the left recurrent leneal nerve we can also find the bifocation of the pulmonary t trunk and bifocation of the trachea now let's talk a bit more about ribs so ribs can be divided into true false or and floating true ribs are also known as the vertebra costal ribs which are ribs 1 to 7 these are ribs that originate from from the vertebrae and join to the sternum through the costal cartilagages. Then you have false ribs or vertebral
3:10 broncoal ribs which are ribs 8 9 10. And these ribs originate from the vertebra and attach to uh the sternum by joining to the cartilagages of ribs six and seven. Finally, you have floating ribs or the vertebra rib free ribs which are ribs 11 and 12. These are the ribs that originate from the vertebra but don't attach anywhere. Our ribs can also be divided into typical and atypical. Typical ribs are ribs with uh similar features typical features and these ribs are ribs 3 to nine. Atypical ribs are different from each other and other ribs and are ribs one,
3:59 ribs two and ribs 10 to 12. Okay. Now let's look at a posterior view of the uh thoracic cav the thorax the rib cage. Here I'm drawing the vertebrae again the clavicle and scapula. And here are the rib uh here are ribs one uh to 12. Here is the scapula and clavicle. Um, and here is the lumbar vertebra 1. Let's talk about the vertebra the vertebrae quickly just for a quick recap. We are looking at a vertebra from a superior view. This is T1 and here is the body. The vertebral fammen is where the spinal nerve goes through spinal
4:44 cord sorry goes through the penduncle. we have the transverse process and then we have the spinus process which we can actually feel when we palpate along the spine. So here is the thoracic vertebra uh six T6 which is very similar to the to the previous vertebra. But something else that is very important to introduce is the facets where ribs articulate and this is um this is specifically for the thoracic vertebrae because they have ribs coming off them. Finally, we have T12. Very much the same with other thoracic vertebrae, but T12 especially becomes bigger when we go towards the lumbar vertebrae.
5:30 Okay. Next, let's look at where organs and other things lie in respect to the thoracic cavity. So, this is an anterior view again. Now, roughly along the fifth uh rib is where the diaphragm sits. important landmarks to remember is uh the midclav clavvicular which is essentially the site from uh if we draw a line from the middle of the clavicle down. So this is midclavicular. There's also midscapula which is a landmark at the back the middle of the scap scapula. The mid auxiliary is the landmark for the lateral aspects of the thorax along the armpits. These landmarks are important to know because of several
6:15 reasons. one of which is to help identify uh where the lung sits in respect to to the thoracic cavity and also uh the the plural flow or the plura itself. So next let's talk about the surface landmarks uh of of the lung of the lung itself and also the parietal plura. So again the plura is uh essentially a membrane uh that covers our lungs and the plura can be divided into parietal and visceral plura. Visceral plur plura is the one that covers all our lungs and the parietal plura is the layer above it.
7:01 So the margins of the lung mid-clavicular it goes to the sixth rib mid auxiliary to the eighth rib and mid scapula the 10th rib. So the margins of the lung mid-clavicular it goes to the sixth rib mid auxiliary to the eighth rib and mid scapula the 10th rib. So if I were to draw it out on this diagram it would be something like this. So um mid auxiliary it goes to the eighth rib the lung and then mid-clav clavvicular it go it is on the sixth rib and at the back midscapula the lung margin is on the 10th rib. The plura here in in blue goes further down. You essentially add two um to find
7:48 the margins of the plura. So mid auxiliary it's at rib 10 midclavicular it's ri 8. So, so margin of the plura midclavicular plus 2 is uh 8, mid auxiliary is 10 and midscapula is 12. I hope that makes sense. Now, the margins of the lung and plura on the left side of the thorax is slightly different because of where the heart is situated. The heart sits somewhere here because remember the aorta goes up and is behind the sternal angle. Again here in red I'm drawing the margins of the lung. The margins of the lung on the left side instead of being
8:34 midclavicular on the sixth rib it is mid-clavicular on the fourth rib. It goes down to being mid auxiliary on the eighth rib. Then everything else is the same. So it's just where the heart is that makes uh the left and right lung margins and plura plural margins slightly different. Just to finish off this diagram, the liver or most of the liver can be found under our ribs for protection. Now let's look at what problems can occur um in the thoracic cavity. Let's look at a pulmonary uh collapse. a a result of a pneumothorax. A collapsed lung is also referred to as
9:21 adalcttois. So normally here is our lung. Surrounding our lung is the visceral plura. Then our parietal plura. In between the visceral and parietal plura we have the plural cavity which helps lubricate the layers and keep keep them stuck together. And here is the cardiac area where the heart sits. Remember air moves in and out as we inhale and exhale. A numoththorax can occur because of something external puncturing the plural layer, the parietal layer resulting in air moving into the plural cavity. This results in air filling the parietal plura uh the plural cavity and forcing the lungs to deflate essentially. So injury results in puncture. Uh so
10:09 injury results in puncturing of the parietal plura. The punctured parietal plura allows air to enter the plural cavity. Air entering the plural cavity compresses the lung resulting in a collapsed lung. However, what we looked at was pneumothorax occurring as a result of an external trauma. What is important to know is that a pumothorax can also occur when the lung and visceral plura is damaged resulting in air filling the plural plural cavity causing a pumothorax as well. This can be seen in lung diseases such as COPD or in tall skinny people who have predisposition for spontaneous pneumothorax. So I hope you enjoyed this video. Thank you for watching.
