AHE (3.2) Part 2 PDF - Shoulder and Arm Muscles

All right moving on to the muscles of the shoulder and arm for this recording alright, so We know some of these that we've seen them before but we're going to start with this anterior view of the axial axis Appendicular muscles here, right? So our pectoralis major is one of these large muscles here...

All right moving on to the muscles of the shoulder and arm for this recording alright, so We know some of these that we've seen them before but we're going to start with this anterior view of the axial axis Appendicular muscles here, right? So our pectoralis major is one of these large muscles here That really acts on the upper limb, but it's found in our torso or thorax And then if we go deep to that we can actually see a pectoralis minor as well We have another small muscle here called the subclavius and it's going to be primarily just associated with the clavicle It's going to add a little bit of stability here, right? So if we look at the muscle actions They're going to be kind of We've already seen these right in terms of our muscles. So the pectoralis major is going to help flex our arm Because it crosses the shoulder joint right here, right? That's an important thing to to think about what joint the muscles are crossing and because it's going to attach a laterally on The humerus when this contracts it's going to help us internally rotate or medially rotate our humerus, right? rotate or medially rotate our humerus, right? That's going to mean bringing The humerus around in this direction, right? Our scapula with these other joints, right? So we're going to have that those muscle fibers kind of running in this direction Attaching from our coracoid process to our scapula here our serratus anterior muscles. We've seen these a little bit before They're going to have a serrated edge They are going to in a quite complex way attached to the anterior aspect of the scapula here So they're going to be able to pull that scapula towards the rib cage towards that thoracic cavity to stabilize it So these two muscles together really help stabilize that scapula, which we know is it plays an important role in the upper limb And then subclavius again, it's going to help depress the clavicle to aid in stability Alright We've seen some of these muscles before actually all of them So here's our trapezius our rhomboids and our levator scapulae. They are going to really help produce and really support Movement of our upper limb right then because they're connected to our axis. We already know those we're not going to cover them here We also have muscles that are going to attach directly from our posterior axis to our upper limb Right so we can call those the scapula humeral joints They're gonna cross this boundary cross this joint. So they are going to have have a role in that So let's go take a look at these more specifically, right? So here's our our scapula. We want to side it right? Here's our nice long border. So that means it's medial Everything's projecting laterally here. So that's gonna be lateral. We have our Supra and infra spinous muscles here We also have our Terry's minor and Terry's major muscle right there You can actually see one of the heads of the triceps break is one of our arm muscles is going to split This that Terry's minor and major so that might be helpful in terms of identification And so if we look at where these muscles are attaching on the humerus here Recall that this is going to be the greater tuberosity The supraspinatus is going to come in and attach to the superior aspect of that when it contracts we're going to be able to Abduct so a be deduction means to bring it above right so it's gonna pour our nose abduct our arm And then both Terry's minor and the infraspinatus they're touching to this posterior aspect So they are going to actually allow us to laterally rotate the arms That means move it in this direction right because they're pulling that lateral aspect posteriorly here. So they have a common Common shared action then if we look at Terry's major It actually attaches very close to where our latissimus dorsi attaches. So that's going to help us or allow us to do medial rotation in the same way that that does so there's our medial rotation because we're pulling the front towards the back here And then we do have our subscapularis We'll see it again later But it's going to sit on the posterior aspect or the anterior aspect of the scapula, right and it's going to sit Nicely in that sub scapular fossa and if you recall from just a little bit ago We'll also have our serratus anterior muscle attaching to this location And these together are going to be not the not the not the Terry's major or the deltoid But these are going to be our rotator cuff muscles. We will see the deltoid here in a minute All right, looking at this view. I think if you're if you're having trouble with the movements of these muscles This is really helpful. So here's the head of our humerus. We have our greater tuberosity here lesser tuberosity here our subscapularis is going to be able to contract and and can help stabilize our Our Upper limb but it's also going to work the super spinatas to house help us Abduct it or bring it above right? So if we pull this our arm is going to raise then we can see Terry's a minor and also the infra spinatas That is going to help us rotate our upper limb laterally here Now if we look at these these These images here I'm primarily going to just show you some helpful little landmarks on these so here again We have one muscle north back of our arm. This is going to be the triceps brachia It's gonna come up in split our Terry's major from our Terry's minor And I think that's really helpful and the other thing to look for is at the spine of the scapula Which is right here. So if it's above it, it's going to be super below it. It's in for a spinus Okay, so clinical correlation so we you will hear a lot about rotator cuff disorders, right Because we use our upper limb a lot and they are going to be some a place where we have swelling or maybe impingement of Vessels and or nerves, right? So where we really see things that impacted are going to be those muscles or the muscle that goes underneath The clavicle and then I need the acromion here. Right? So here's our acromioclavicular joint You can see that it's limited in terms of its space. So if we have swelling in this area We're gonna have things impinged right or squished So excessive fluid build-up and so forth can cause issues with this. So because our super spinatas Helps us abduct our arm. Helps us abduct our arm. We are going to have trouble lifting our arm above our head When this muscle and the its innervation is impacted, right? So this can happen through repeated trauma. Sometimes we see this in athletes as well But again these structures the the acromioclavicular Ligaments and joint as well as the acromiocluorochromial ligament are going to really cause that construction All right muscles of the arm there's only well, there's five but four is what we're gonna think about so Before we get into here. We want to think about how these are organized we've already learned about our development and how our limbs are gonna rotate in the seventh week and That's also going to impact what we see in terms of where our flexors are going to be where our extensors are going to be So in general or this we have this really nice theme here Within our brachial fascia means here to term brachial that means arm within that fascia You're gonna have two compartments, right? You're gonna have two compartments, right? This is surrounded by this really thick dense connective tissue You can see that right here, right? So if you have compartment syndrome that means that you have swelling within here within here on your muscles, right? So in our in our arms specifically here, we're gonna have anterior compartment be our flexor compartment and then our posterior Up here and then our posterior compartment are going to be our extensors So the ones in the front are going to help flex our arm The ones in the back are going to help extend our arm. We'll see the same thing in our forearm This is going to be covered or contained by the anti brachial fascia. So after the arm fascia, right? So these muscles will be divided by an interosseous membrane. All right, this connective tissue Right that spans between these bones The anterior compartment again is going to be our flexors flexors of the digits flexors of our wrist While the posterior compartment is going to hold the extensor muscles. This is really going to help us with the names of the muscles Okay So in the arm, we have four muscles that we're gonna look at We have three on the front and one on the back the anterior compartment are going to help us flex Whether that's our shoulder or our our elbow here, right? So in this image, we have the biceps brachii the two-headed biceps brachii we have That's going to come up and actually Attach on our scapula Here when these muscles contract we're going to help flex our arms It means bring your arm forward if you kind of think about it deep to that We're gonna have the brachialis muscle right here. This is going to cross our elbow, right? The brachialis then is going to help us flex our weakly flex our elbow and then we're gonna have the coracobrachialis Lovely its name for what it attaches to that coracoid process of the scapula to the humerus So the arm so coracobrachialis is going to also again help flex So they're all flexors whether it be the shoulder or the elbow just depends on what joint they cross All right, when we look at our posterior view, we know it's posterior because we can see this nice spinous process Here's our our spine of the scapula. There's our chromium. This is our triceps brachia. You can see two of the heads here Here's the one head that's coming up our medial head that's coming up to split the Terry's minor and major This the third head is going to be in deep right here in touch to the humerus This is going to help us extend our shoulder which really means pushing our arm posteriorly there Alright, we have one more muscle called the antonius. It is going to weakly Extend our elbow. It's a little guy right here I like the antonius though because it tells me that I'm looking at the posterior view. looking at the posterior view. It's pretty distinctive in this area So here we can look at those different Actions, right? So we have extension and then we'll have flexion as well the other direction And we can see that all of these are going to flex because they're in the anterior compartment And these are all going to extend because they're in the posterior compartment And that is the end of the second recording