Alright guys! In this video we're going to take a look at the arm. So we're gonna look a lot of the muscles of the arm. Let's go ahead and dive right in. So if we start right here, we're going to have this muscle right here, this is called the pectoralis major, this is the pectoralis major right here. And again we're going to keep saying the function so we can get that drilled into you guys head. The pectoralis major, it flexes the whole arm at the shoulder joint and adducts at the shoulder joint and it also does medial rotation at the shoulder joint. Ok that's the pectoralis major. Right here, this big superficial muscle right here, this is called the deltoid and there's three heads, anterior, middle, and posterior head of the deltoid. Now the deltoid muscle in general it does abduction at the shoulder joint, but obviously you have three heads. So the anterior head could technically do flexion at the shoulder joint. The lateral head could do abduction and the rear head of the deltoid could do extension at the shoulder joint. That's something that you could technically say but in general we usually just say deltoid muscle is abduction at the shoulder joint. Okay now, what I'm going to do here is I'm going to turn it over alright. So now we're going to take a look here, this is a deep muscle you can see this cut just cut chunk of muscle, this is the trapezius muscle, the superior trapezius. But underneath this thick trapezius muscle, we have the supraspinatus, it sits in the supraspinous fossa, and it actually inserts with the supraspinatus tendon and helps to be able to do abduction at the shoulder. So it does abduction at the shoulder, so again supraspinatus muscle right here, does abduction at the shoulder joint alright. So if I turn a little bit here, again guys what I'm going to do is I'm going to take the deltoid muscle off, so we can see this big superficial muscle. I'm going to take that off here, so we can see some of these deeper muscles. Again so, if you look here, I got this big, big chunk of muscle all right here. All this big chunk of muscle, this is all the infraspinatus and the infraspinatus again, it laterally rotates. Okay so it helps to be able to externally rotate or pull the arm back or the humerus back right? That's what it's design is to be able to do lateral rotation or external rotation. This muscle right here that we can see this is actually going to be the teres minor. So this is the teres minor and the teres minor does the same thing as the infraspinatus, it does lateral rotation or external rotation of the shoulder. That means that the infraspinatus and the teres minor are synergist to each other for that action. And if you look her,e we got another big chunk of muscle right here this is called the teres major and again the teres major does extension at the shoulder joint, it does medial rotation and it also does extension at the shoulder joint. So if you think about it again, he does medial rotation the teres minor and infraspinatus does lateral rotation. So these two are antagonist to one another for that action. Ok so again infraspinatus, teres minor, teres major. Now we're going to do is, we're going to flip this guy over so we can take a look at two more muscles. Here are actually three more muscles alright guys. Now we're on the anterior side of scapula, so if you look here we have this muscle right here sitting in the subscapular fossa, this is called the subscapularis and the subscapularis does medial rotation. So it helps to do internal rotation, pull the arm basically forward right at that shoulder joint right. So that's again, that is the subscapularis. You can see a tiny chunk here of the latissimus dorsi, because it's going to go insert onto the humerus. Here you can see the little chunk good latissimus dorsi right there and then you can see the chunk here of the teres major too. So you got subscapularis and then you got latissimus dorsi and again latissimus dorsi does extension at the shoulder joint, he does medial rotation at the shoulder doing and he does adduction at the shoulder joint. So he's a synergist for all those actions with the teres major all right. And he'd also be a synergist to the subscapularis because these two both media rotate. Alright another muscle that attaches up here at the coracoid process, this is actually gonna be called the coracobrachialis. So here you got the coracobrachialis muscle right there. So the coracobrachialis runs kind of all the way down here and what it helps to do, is helps to be able to flex the whole arm at the shoulder joint and it does adduction at the shoulder joint ok. So, the coracobrachialis again does flexion at the shoulder joint and it does adduction at the shoulder joint. So with that taking into consideration, the coracobrachialis could be a synergist to latissimus dorsi and it could be a synergist to the teres major because all three of these muscles do specifically adduction okay. And again you can see a chunk of the pectoralis major. Now we're going to do is, we're going to go over here. We're going to take a look at the biceps muscles. Alright so let's take a look here at the biceps muscle. So if you can see here, we have a good chunk of the biceps brachii muscle. It's actually two heads, there's a short head and then there's a long head. I'm going to show you the long head in a better view, but here we have the short head. And the short head actually comes up here and attaches to the coracoid process up there. So that's one of the attachment sites of it. Alright and then if you look, so that's actually where the origin would be. And so that's going to be the short head of the biceps, right there is the long head of the biceps, and it attaches up there, that's called the super glenoid tubercle. But we're just going to categorize them as just one big muscle, the biceps brachii. And in general, this whole muscle as a group works together to do flexion at the elbow, flexion of the whole forearm and then it also supination of the palms, where it helps to be able to hold, if you think about upholding a bowl soup and pronation is dumping a bowl of soup. Alright, so that's what it helps to be able to do is again, flexion of the forearm, flexion at the elbow and it does supination of the palm. And as you can see here, we can still see the coracobrachialis right there. And again flexion at the shoulder joint for this guy and adduction at the shoulder joint for him. So now we're going to do is, we're going to flip it over, till we can see the a better view of the brachialis and the long head of the biceps brachii. Alright, so if we look here we can see this right here. This one on the outside here, this is the long head of the biceps and again, we already know we already said what it does. We're going to treat them as a group of the biceps brachii. It's a flexion of the forearm and supination of the palm, ok. And if we look here, this is the brachialis muscle. Shis is the brachialis and the brachialis muscle helps to be able to do flexion of the forearm, flexion at the elbow. So if you think about it the brachialis muscle is a synergist to the biceps brachii for flexion of the former flexion at the elbow. Ok. So that covers these bicep muscles right there. Now what we're going to do is, we're going to flip it over to the posterior part of the arm, so we can see the tricep muscle. Alright so, if we look here we have three heads of the tricep. This one right here is the lateral head of the triceps. So this one right here is a lateral head of the triceps, this one right here is the long head of the triceps, and then this one right here is the short head or the medial head of the triceps. All of these make up what's called the triceps brachii right. So the triceps brachii helped to be able to do what's called extension at the elbow or extension of the forearm. There's another muscle that's a tiny little one down here it's called the anconeus. And the anconeus also does extension at the elbow or extension of the forearm. So we think about the anconeus and the triceps brachii muscles are both, all of them are antagonist to the biceps brachii and the brachialis for these guys doing extension at the forearm and the bicep muscles doing flexion at the forum. So these two guys are going to be antagonist to one another, whereas the triceps brachii and the anconeus would be synergist to one another. Alright guys, so what we're going to do is we're going to look at the muscles of the forearm, the extensor side. So if you see here, we have this muscle right here. First this is called the brachioradialis. That's the brachioradialis. And the brachioradialis does flexion of the forearm or flexion at the elbow joint. Im going to turn a little bit. Extensor carpi radialis longus right there and as you can tell by the name it extends carpi, extends the wrist. So extensor carpi radialis longus, it extends the wrist. Lo and behold, here is extensor carpi radialis brevis, it also extends the wrist. So longest just means it's a lot longer, brevis means it's shorter. Turn it over here, this is the extensor digitorum. Says the name extends the digits. This is extensor digiti minimi, ok. Extends the digits. This right here is going to be the extensor carpi ulnaris. Alright, so extend the wrist. So that covers all the muscles on the extensor side. What we're going to do is, we're going to flip it over and we're going to cover the flexor side. Alright guys, if you look right here we have the flexor side. So this is going to be called the pronator teres and he pronates the palm. So again remember if you hold the bowl soup, it's supination. If you dump the bowl soup, it's pronation. So he does pronation of the palms, that's the pronator teres right here. Next to him, is going to be the flexor carpi radialis, so it flexes the wrist. Next to him, is the palmaris longus and the palmaris longus also flexes the wrist. And we have one more over here, this is called the flexor carpi ulnaris and this one also flexes the wrist. Now we have another set of muscles that I want to cover that are deeper here. I'm going to take this off here. Alright guys, so now we're going to take a look here at the deeper part. So if you look here, this is the flexor digitorum superficialis, all this muscle right here ok. And to get to him, we had to take off all this layers that we just showed you right here. So we had to take off the pronator teres, we had to take off the flexor carpi radialis and we had to take off the palmaris longus. So if I come take that off again, you can see there the flexor digitorum superficialis. And the flexor digitorum superficialis flexes the digits and then eventually the wrist ok. So if you think about it, he is a synergist to the flexor carpi radialis, he's also a synergist to the flexor carpi ulnaris for flexion at the wrist. Okay, now i'm going to do is, I'm going to take the flexor digitorum superficialis off, so that we can see the deeper layers. This right here guys, the flexor pollicis longus right there. So flexor pollicis longus, then if you look over here, this is going to be the flexor digitorum profundus right there. So again we got the flexor pollicis longus, which flexes the pollex. And then over here we got the flexor digitorum profundus which flexes the digits. Okay, so these two muscles right here are going to be deep to that muscle that we just talked about, being the flexor digitorum superficialis. Now, I'm going to turn it over here more and you can see this really, really deep muscle right here. This is called the supinator and the supinator like we said it supa nates the palms, that helps to hold the bowl of soup ok. That's the supinator muscle right there and if you think about it the supinator is a synergist to the biceps brachii right, for supination at the palm. And it's going to be an antagonist to the pronator teres, which pronates the palm. There is another pronator muscle that you can't see on this, it's called the pronator quadratus it's going to be closer down here to the wrist region, but that's another muscle. So you could also say an antagonist to the supinator, is not only the pronator teres but the pronator quadratus ok. So now, we're going to take a look here at the thumb. These are the thenar muscles, thenar eminences. If you look here, we got this tiny little muscle right here, that's going to be the opponens pollicis right there. This muscle right here is going to be the abductor pollicis brevis and this one right here is going to be the flexor pollicis brevis. Right there flexor pollicis brevis and then 30 right there there's going to be the adductor pollicis brevis. And this covers the thenar muscles right there. Alright guys so now we're going to look over here at the hypothenar muscles. So over here we have this one right here, this is the opponens digiti minimi right there. And then this one right here is going to be the abductor digiti minimi. And if I flip it inwards in here, this last one right here is going to be the flexor digiti minimi. Alright guys, so that gives us basically an overall look at the entire arm and all the muscles that actually contains.