Okay, friends, it's a pleasure to greet you. Today I bring you a video about the famous shoulder joint, also known as the glenoral joint, although throughout the video we will understand that the shoulder joint is not just the glenoral joint, but rather a set of two or even three joints. The number of joints that they will tell you correspond to the shoulder joint depends a lot on the literature that you use. So, before we begin, I invite you to subscribe to my channel. Here in the lower right corner you will see a link that says subscribe, so you can click there, so you subscribe to the channel and help me so that I can upload more anatomical content for this channel.
So, basically, the shoulder joint is a joint that occurs between the head of the humerus. I invite you to watch my videos about the humerus so that you fully understand the anatomical configuration of this head and the glenoid cavity of the scapula. That is why this joint is called the glenohumeral joint. Something very characteristic of this glenohumeral joint is that its contents, that is, the head of the humerus, are larger than the container, that is, the glenoid cavity of the scapula.
That is why, since the container is much larger than the contents, it is so common for this joint to dislodge or sprain, as you want to call it. A dislocation is nothing more than the loss of contact between two articular surfaces. Okay?
So, well, this glenohumeral joint is the main one. It is the one we generally know as the shoulder joint, but it turns out that this shoulder joint is also made up of the articulation that occurs between the outer third of the clavicle and the acromion of the scapula, this being the acromioclavicular joint. In order for you to fully understand how this shoulder joint and the acromioclavicular joint work, it is vitally important that you know the classifications of the joints. I have a very good video on that classification, I'll leave it at the end of this video.
And if you're not familiar with joint classification, I invite you to watch that video first and then return to this video on the shoulder joint. So, from the point of view of joint classification, This glomerular joint is a synovial joint, without a doubt, just like the acromioclavicular joint, but it turns out that within synovial joints there are seven subtypes and that's what you need to know. This glial-narrow joint specifically is of the anarthrosis subtype. The other name these anarthrosis joints receive are spherical joints. because they are generally a sphere or an almost complete hemisphere that fits over a large cavity and this allows a great amount of movement.
In fact, arthritic joints are the joints in the human body that have the most movement in the body. They are capable of moving in all axes, that is, in the three axes that we know. It is a multi-axial joint and by moving in three axes it allows me to make six movements.
I can do flexion, extension, abduction, adduction, internal and external rotation. And together, these six movements are what is known as the circumference movement. So this joint in particular is the most mobile joint in the entire body, this glenumeral anarthrosis. But on the other hand, the acromioclavicular joint, despite being a synovial joint, is a flat-type joint.
That is the subtype. are also called an arthrodiatype joint. That is why the external third of the clavicle is flat and the acromion of the scapula is flat. So these allow sliding movements, but on a single axis. However, they are still both synovial type joints.
So, you know that every joint needs ligamentous structures that fix it, that let's say reinforce it to the joint. Those are precisely the ligaments. A ligament is nothing more than a fibrous structure that helps fix and strengthen a joint. So, here in the case of the shoulder, the names of these ligaments are very easy, since when you see the origin and insertion of this ligament, you will already know the name of the ligament. So, like any synovial joint, it is surrounded by a fibrous capsule.
This fibrous capsule is reinforced first by the coracohumeral ligament. The name itself tells you that this has to be a ligament that comes from the caraco process and leaves the scapula towards the humerus. And precisely this ligament that you see here is the coracoral ligament.
That is the first ligament that reinforces the fibrous capsule of this gleneral joint, followed by the humeral ligaments. What happens? In some books, these humeral ligaments will be called gleneral ligaments. Why? Because they are the ones that go from the glenoid cavity or the edges of the glenoid cavity to the humerus.
There are three. A superior one that you see that is below this one, which is the coracoral. would be the superior humeral ligament or superior glenoural, then the middle glenoural ligament or middle humeral, and finally the glenoural ligament or inferior humeral.
These three together are what are known as the humeral ligaments or glenoural ligaments. Now, there is something very characteristic of this fibrous capsule, this joint, and that is that it has an extension downwards, towards the diaphysis of what is the humerus. Thanks to this extension.
I can do the abduction movement and bring the shoulder completely out. But it is also thanks to this extension that an anterior or inferior elucidation of the shoulder is so frequent. It takes advantage of the most frequent elucidation of the shoulder in the anterior and inferior direction and it is precisely because of this ligamentous weakness that exists in that area.
So, finally, this glomerul joint, that fibrous capsule, is going to be reinforced by this ligament that goes from the greater tuberosity, also called the tracheate. to the lesser tuberosity, which is the trochan. That ligament is called the transverse ligament of the humerus or transverse humerus. You will also find it in many books with the name of the dissipital ligament.
Why? Because remember that this channel that I had between the greater and lesser tuberosity was the bicipital canal. So, this ligament closes and wraps around and protects this tendon which is the tendon of the vice brachialis, specifically the long head of the ice brachialis.
which is why it is also called the bicipital ligament. Now, these ligaments are what reinforce this glomerul joint. It turns out that the acromioclavicular joint also has a series of ligaments that fix it and make that joint stay there.
First, we're going to have the coracoclavicular ligaments. The name itself tells you that they go from the coracoid process of the the scapula to the clavicle. They're basically going to be these two ligaments that you see here, a ligament together with the coraclavicular ligaments, a more medial and posterior ligament which is the conoid ligament, also called the conoid ligament, and a more lateral and anterior ligament, which is the trapezoid ligament, also called the trapezoid. These ligaments, which are the coracoclavicular ligaments, are what guarantee that this clavicle doesn't dislodge on the acromion. In fact, when they tear, There absolutely has to be an acromioclavicular dislocation, because they're what keep that joint there.
So, in addition to these ligaments that join the scapula and clavicle, we agreed that these here join the scapula and humerus. There is another set of ligaments that join the scapula to the scapula, which are the scapular ligaments, that is, they join part of the scapula itself. Those are going to be the first, the caracoacromial ligament.
which would come from the coracoid process to the chromium. See, the coracoid process is not joining any bones, it simply goes between two parts of the same scapula. And finally, the transverse ligament of the scapula, which is closing the coracoid notch.
That is why this ligament, in addition to being called the superior transverse ligament of the scapula, is also called the the coracoid ligament. a ligament that can become coracoid and transform the coracoid notch into a coracoid orifice. If it becomes ossified, which is something that usually happens. Now, you may say, well, in addition to these ligaments, I see two here that I didn't name.
It turns out that these are not ligaments. These two that you see cut here are tendons. Remember that a tendon is not the same as a ligament.
A tendon is an extension of the muscle that the muscle uses to insert itself into the bone. So, Specifically this is the tendon of the supraspinatus and this is the tendon of the subscapularis muscle, which also help to reinforce the joint, as we are going to see right now. So, look at this image.
This is a lateral view. I'll locate them. This is anterior, this is posterior.
We are looking at the glenoid cavity, which as I told you, this glenoid cavity is so small, it has to extend through this fibrous labrum. That is what is known as the glenoid labrum. That's what serves to extend the cavity and prevent the head of the humerus from coming out of there at all costs. So, what you see here is the tendon of the long head of the vice brachialis that we saw just now that goes through the bicipital canal. So, locating ourselves anatomically, this would be the superior humeral ligament or superior glenumeral ligament.
This would be the middle glenumeral ligament, and this inferior glenumeral ligament. Notice that there are many spaces between these ligaments and that's why it's easier for the shoulder to come out forward through those spaces. Now, in front of these glenumeral ligaments, remember that there was the tendon of the subscapularis muscle. In fact, I remind you, look.
the middle glenumeral ligament and in front of it the tendon of the subscapularis muscle. Notice that above the superior glenumeral ligament or superior humeral ligament is the tendon of the supraspinatus muscle. Back here would be the infraspinatus tendon and this would be the teres minor tendon. Together, the teres minor, infraspinatus, Supraspinatus and subscapularis are what make up the muscle tendon cuff.
also called the rotator cuff, which is a very important structure that helps hold that joint there, to reinforce it. Now, this ligament that is here, look how it goes from the acromion to the scapula. This is one of the scapular ligaments, sorry, of the scapular ones that goes from the coracoid process to the acromion. So this is the coracole ligament and this one here that is just in front and above, the superior humeral is the coracohumeral, as we see it here.
Coracohumeral. This is the one we are seeing cut over there. This structure that you see here, this is a bursa.
You will see that in most of the important joints of the body there is a bursa. Bursae are synovial extensions, also called synovial sacs, that help reduce friction between ligamentous structures, tendons, and the bones themselves. In other words, they act as a spring.
That bursa that is there, as it is under the acromion, is the subacromial bursa. Here we can see it much better. This would be the tendon of the supraspinatus muscle.
This would be the tendon of the deltoid muscle. Look at the extension that I was telling you about from the capsule through the inferior humeral ligament. And this is where it is easier for the shoulder to elongate. This would be the superior humeral lineation.
So this would be the inferior humeral lineation. This bursa that is here at this level is called the subacromial bursa and here it is called the subdeltoid bursa, which frequently fuse. This image looks spectacular.
This would be the coracoacromial ligament and here you can clearly see the fusion of the subacromial bursa and the subdeltoid bursa. This would be the transverse ligament of the humerus, which I also told you is called the transverse humeral ligament or vispital ligament. This would be the coracoid ligament or superior transverse ligament of the scapula. Likewise, this tendon that you see here is the supraspinatus tendon.
which we see inserting here and this would be the tendon of the subscapularis muscle. So, friends, that's all for the video on the shoulder joint. Don't forget to subscribe in the circle that appears here, give it a like, share it and you can also follow me on Instagram at at JuanPisouzaAcuteNchez1315.
Here's the link so you can watch the video on joints, the generalities so you can understand this video, the video on the scapula and the video on The Humorous. Thank you very much. M.