074 The Structure Of The Clavicle
In the previous video, we mentioned clavicle as part of the shoulder girdle. In this episode, we learn more about it and the parts we find on the bone itself.
Transcript of Today’s Episode
In this video, I’m going to be talking about the structure of the clavicle, more specifically, I’m going to first talk about the ends and the shaft of the clavicle. Then, I’m going to talk about how to determine whether it’s a right or left clavicle, and then, the structures that are on the clavicle.
By the end of this video, you’ll know exactly how to identify different aspects of the clavicle.
Let’s get right into it.
Here, I’m looking at a clavicle. We spoke a little bit about the clavicle in the previous video. I want to point out a few features of the clavicle.
First of all, over here, we have the acromial end of the clavicle. This is where it articulates with the acromion process of the scapula, that acromioclavicular joint that we spoke about in the last video. This sternal end of the clavicle where it articulates with the manubrium of the sternum, the sternoclavicular joint.
The acromial end and the sternal end.
Then, of course, the main body of the sternum, that is what we’re going to call the shaft. We have the two ends and the shaft of the sternum.
One of the features I want to point out here, if you look over here on the x-ray, this chest x-ray, you’ll see that you can also see once again, we have the sternal end, and we have the acromial end.
What you can notice in terms of a difference is, this acromial end here, let me do that again, this acromial end here, it’s much flatter. If you come over here to the sternal end, you’ll see that it’s more rounded on the sternal end. That’s one of the distinguishing features that you can see. You can’t see it as much in this picture. But, you do see that this is a little flatter than this that’s a little more rounded. The sternal end is a little more rounded.
Then, what else you’ll notice is that as we look at this clavicle, this is going to be a left clavicle and there are some features that kind of give that away.
Right here, you can see that there’s kind of a curvature. What you’ll notice is that there’s this anterior convexity. It curves forward the medial 2/3, let’s say from about here all the way down, that medial 2/3, that’s going to be convex anteriorly, so, curve anteriorly.
Then, the lateral 1/3 is going to be convex posteriorly. It curves backwards. That’s one differentiating feature.
If you want to tell if it’s a left or a right clavicle, what you’re going to do is you’re going to make sure that the acromial end is distal, the sternal end is proximal, and that there’s this anterior convexity for the proximal 2/3, and a posterior convexity. Once you have it in that position, you’ll be able to tell that, “Okay, this is left.” If it were right, it would be the exact opposite.
What I’m looking at here, I’m looking at the superior surface of the left clavicle. This is looking from the top down. Let’s look at the inferior surface which is what you see here. I’m basically just taking this one and flipping it over.
I want to point out a few structures.
First, let’s deal with the distal structures more on the acromial end. Here, you can see that there’s a tubercle here. We’re going to call this the conoid tubercle, and then, here we see the trapezoid line. So, the conoid tubercle, the trapezoid line, and these are all on the inferior aspect.
These are going to be significant when we talk about the ligaments that connect to this tubercle, the conoid tubercle and trapezoid line. I’m going to talk about that in a later video.
Then, we also see on the distal end or the acromial end coming down to the acromial end, we have the deltiod tuberosity or the deltoid tubercle. You can see that here also. And, you can assume by right now that that’s going to have something to do with the deltiod muscle, and we’re going to talk about that in a later video. The deltiodeus has to do with the naming of this tubercle.
Then, let’s look right here on the inferior aspect, we see we also have a groove that we’re going to call the subclavian groove. That has to do with the subclavius muscle and we’re going to talk about that later.
Then, as we go more medially to the proximal end, we’re going to see there’s a tuberosity here that we’re going to call the costal tuberosity.
I’m not going to go through all of the structures on it because we’re going to deal with some of the other structures later. But, for now, I want you to remember the ends. I want you to remember some of the features of the curvatures and so on, and be able to determine left and right, some of the tubercles and tuberosities, the deltiod tubercle, the conoid tubercle, and the trapezoid line, the subclavian groove and the costal tuberosity.
That’s pretty much it. Let us do our review quiz. As usual, if you would like to review it and test yourself, you can turn the volume down. I’m going to point to the different structures and you can answer it with me.
First, let’s start with the simple, this is the acromial end. Over here, we have the sternal end. This would be the shaft. Then, if we were to look at the structures on the clavicle, here we have the deltiod tubercle. Over here, we have the conoid tubercle, and we have the trapezoid line. We have the subclavian groove, and we have the costal tuberosity.
All right. Those are all the structures for now. That’s pretty much it for this video. If you would like more videos like this and other resources to help make Biology fun, visit the website at Interactive-Biology.com for more Biology videos and other resources.
This is Leslie Samuel. That’s it for this video and I’ll see you on the next one.