hi right guys in this video we're going to talk about the muscles of the anterior thorax we're going to talk about uh each one of those muscles in each of these three models so that we can get a kind of a different variation and look at the different muscle fibers and look at the superficial and the Deep layers um also what I want to be able to do in these videos is talk about synergists and antagonists so um before we do that what I want to be able to do is give us the defining terms of what a synergist is and what an antagonist is so a synergist is like let's say you have two muscles they both perform the same action okay so if they both perform the same action those are synergist to one another okay so they work together to be able to perform that function antagonists are going to be two muscles that oppose each other so for example let's say that the biceps break eye we'll talk about it it flexes the forearm the triceps break ey is going to oppose that and extend the forearm so we're going to talk about a lot lot of these guys in this video all right guys so if we look here you see this big muscle number 58 right here this huge muscle right here this muscle is called the pectoralis major so this is called the pectoralis major the pectoralis major has uh three primary functions those being it flexes the whole arm right at the shoulder joint it also adducts the whole arm at the shoulder joint meaning it pulls the arms in all right and it also helps to be able to immediately rotate the arm or internal rotation at the shoulder joint so those are the three functions of the pectoralis major so a synergist to the pectoralis major could be someone else who flexes the forearm that could be like the Coro brachialis um you also could find another guy who does uh adduction at the forearm and that could be the coral brachialis or the latissimus dorsi or the terus major and then we could he also does medial rotation right so someone who else does medial rotation could be like the subscapularis the latissmus dorsi the terus major tons of those different muscles right so that could be an example whereas if you want an antagonist to any of those for example he flexes the whole arm at the shoulder someone that would extend the whole arm at the shoulder like the terus major or latis dorsai uh he add ducts at the shoulder so he'd want to be able to have a muscle uh antagonizing him who would abduct at the shoulder and that would be like the deltoid muscle or the super spinatus and then again he immediately rotates so you'd want someone who laterally rotates like the infraspinatus or the terus minor okay so those are some muscles right there for that that's just giving you just a quick preview of the pectoralis major and some of its synergis and antagonist so if we come over here uh you see these two muscles here 63 and 62 62 is the external intercostal so this is the exter costal and there's another piece of it another piece right 63 is the internal intercostals so this is the internal intercostals right there also the external intercostals help to elevate the ribs so they pull the ribs up so they provide elevation of the ribs for inhalation so so you can take in deeper breaths right uh the internal intercostals they depress the ribs they pull those ribs down for like a forced exhalation so if you think about it these two are antagonists to one another for that function he elevates ribs and he depresses the ribs that being elevating is going to be the external intercostals depressing is the internal intercostals now what I'm going to do is I'm going hit another muscle over here and if you can see it over here this is going to be called the serratus anterior all these guys right here are the serratus anterior and the serratus anterior muscle it's responsible for being able to protract the scapula so that's going to be protraction of the scapula someone who else who could protract the scapula could be like the pectoralis minor and someone who retracts the scapula you have a ton of muscles that could do that we could say the ROM boids major minor um we could say the trapezius muscle could also do that so those could be some type of antagonist to the seratus anterior now if we come over here if we look here we're going to be able to see another view of some of these skeleton muscles we talked about so on this one you can see the pectoralis major right here that I'm scraping number 30 uh 39 it you can see the pectoral fascia though of the the platisa muscle kind of sitting over it but this is the the pectoralis major and we already talked about what its functions are um flexion at the flexion at the shoulder adduction at the shoulder and medial rotation at the shoulder but it's also a very superficial muscle and so if I take off this layer here we can see some of the deeper layers of the pectoralis major so if we look underneath the pectoralis major you can see this muscle right here this muscle is called the pectoralis minor so the pectoralis minor what it does it helps to be able to protract the scapula so it's insertion point is the Coro process of the scapula and the origin is going to be ribs two through five so what it does it pulls again it pulls the scapula forward right so that's going to be the pectoralis minor um and again it would be a synergist to the seratus anteria that we talked about who also protracts the scapula if you look here 42 and 43 42 and 43 42 being the external intercostals and 43 being the internal intercostals we know that the external intercostals Elevate the ribs right and then 43 the internal intercostals depress the ribs so they're going to be in tagonist to one another another muscle that you can see here I'm going to pull this out here it's actually going to be this muscle right underneath the clavicle right there it's called the subclavius and the subclavius depresses the clavicle so there's another muscle that you can see in this model all right so that covers the muscles that I wanted to show you in this model we're going to move on to one more model so that we can take another look at some of them all right gu so if we look here we can see another view of some of those muscles we talked about so if you look here this muscle right here this is the pectoralis minor we already talked about him and again we know that he protracts the scapula okay so he'd be a synergist to the specifically the seratus anterior but he would be an antagonist to like for example the trapezius or the Romo's major minor and then we talked about these guys external intercostals right here internal intercostals right there these two are antagonist to one another because the external intercostals Elevate the Ribs internal intercostals depress the ribs right and then over here we can see the seratus anterior but we have an even better view of them over here we can see the seratus anterior right there and that's a nice view of them and we know that the serus anterior is designed to be able to protract the scapula and so like we said it would be a synergist to the Petrus minor but an antagonist to uh as we said the um romboid major minor or the trapezius so if we take a look here we're going to see one more view of the pectoralis major right here again this is the P teralis major right there and again as we already said flexes the whole arm at the shoulder joint adduct the shoulder joint adduct at the shoulder joint and it also does medial rotation okay so again it could be a synergist to the coral brachial for flexion at the shoulder and adduction at the shoulder it could be a synergist to the subscapularis for medial rotation it could be an antagonist to the infraspinatus and the terius minor for lateral rotation it could be antagonist to the teres major and the latissmus dorsai for uh they extend at the shoulder and he flexes at the shoulder so he could have a ton of different synergis and antagonist this just depends upon what action okay all right guys so that basically gives us everything that we need to know about some of these anterior muscles of the thorax all right so we're going to take a look at the abdominal wall muscles now so if we look here I'm going to go through each one of these abdominal wall muscles from superficial to deep so from the most top layer or The Superficial layer all the way down to the deepest inner layer okay so the first one the most superficial layer of the abdominal wall is right here this guy looks like it's going down the panss the fibers look like it's going down the pants this is the external oblique okay so the external oblique what it does is it helps to be able to flex the vertebral column and it compresses the contents of the abdomen to increase the intraabdominal pressure to assist an exhalation okay forced exhalation now then if we come over here I'm going to turn it for you guys you can see over here we got the internal oblique and the internal oblique if you look at the fibers it looks like it's going up your shirt or it's going up towards that right shoulder so the internal oblique is going to be the second superficial lay so it goes external oblique then underneath that is going to be the internal oblique and the internal oblique does the same thing it flexes the vertebral column and it compresses the contents of the abdomen to increase the intraabdominal pressure to assist in forced exhalation then if we look at this next muscle layer right here which appears like it's going straight up and down this is the rectus abdominis so this is your six-pack muscles right so this is the next deepest layer so it goes external oblique internal oblique and then it goes rectus abdominis and the rectus abdominis is going to again Flex the vertebral column and compress the contents of the abdomen to increase intraabdominal pressure to assist an exhalation forced exhalation there is another muscle that you can't see it's even deeper than this one it's called the transversus abdominis and it does not Flex the vertebral column all it does is compress the contents of the abdomen to increase the intraabdominal pressure to assist and force exhalation but I'm going to show you guys that muscle on another muscular model and we have another last thing we have this other connective tissue aerosis running right down this which is called the line Alba and that's a good connective tissue structure some of the muscles actually insert onto that all right guys guys like as promised I told you I would show you guys the transverses abdominis right here so if you see what we did is we just took the chest plate of this uh model off of one of the torsos so you could see it so if you look here this muscle which appears like it's going side to side this right here is the transversus abdominis and that's the deepest layer of the abdomen okay and so again just remember that this one does not Flex the vertebra column all it does is compress the contents of the abdomen to increase intraabdominal pressure to consistent forced exhalation but as you can see you can still see the rectus abdominis here and you can even see the external oblique over here too okay so again that gives us basically the view of the muscles that we're going to need to know okay on this 12 chest plate all right so now we're going to do a quick recap of the abdominal wall muscles but we're just going to look at it on another model so that we can get a different view of those muscles what they look like their functions again and then there happens to just be another muscle on this model that I want also want to show you guys so again we're going to go from superficial all the way to deep and it's just going to be more of a quick recap again guys so this muscle right here looks like again it's going down the pants this this is actually going to be the external oblique and again flexes the vertebral column and compresses the contents of the abdomen to assist and force exhalation all right guys so now we're going to come over here and we're going to take a look at the internal oblique the internal oblique if you remember it looks like the fibers are are going up the shirt or towards like your shoulder your right shoulder here so that's going to be the internal oblique and the internal oblique again flexes the vertebra column and compresses the contents of the abdomen to increase the ad inra abdominal pressure to assist en Forks forced in exhalation next one rectus abdominis appears like it's going up and down right so this is your sixpack muscles flexes the vertebra column and it compresses the contents of the abdomen to increase intraabdominal pressure which helps to assist en forced exhalation all right um again you can't see the transversus abdominis it would be the deepest layer and it still does and it actually moves from left to right side to side right it does not Flex the vertebral column it only compresses the contents of the abdomen to increase intraabdominal pressure to help to incre uh assist in forced exhalation okay so again that gives us his muscles from superficial to deep again external oblique internal oblique rectus abdominis transverses abdominis again this connective tissue aerosis here is the Linea Alba right there and there is a muscle right down here and it's called the pyramidalis and it actually inserts on the linear Alba and helps to tense the linear Alba okay