Let’s move on and talk about the next bone in the shoulder girdle — the proximal humerus. Let’s learn about the grooves, tuberosities and other parts found on it.
Transcript of Today’s Episode
In this short video, I’m going to be talking about the structure of the proximal humerus, the third bone involved in the shoulder girdle.
Let’s get right into it.
Here, we’re looking at the proximal humerus. There are a number of structures that I want to point out. The structures are right here identified for us. But, before I talk about those structures, I want to talk about the fact that when we look at the humerus, and we look at the head of the humerus, it projects medially. Right now, we’re looking at the left humerus so, it’s projecting medially.
It’s also projecting superiorly and posteriorly, so that’s going down. If I want to tell if this is a left or a right humerus, what I would do is I would take this humerus, and make sure that the head is pointing superiorly, posteriorly, and medially. That will show whether it’s left or right.
All right. So now, for the structures of the humerus.
First one I want to point out is the head of the humerus. We’ve spoken about that before, but that’s right here. But then, we also have these two tuberosities. It’s identified as here. But, I’m going to call them the greater and the lesser tubercles. You can see it here. This is the greater one and it’s going to be bigger and this is going to be the lesser tubercle and that’s going to be smaller.
If I look over here, this is also a left humerus. We have the lesser tubercle and we have the greater tubercle.
In between these tubercles, we have this little groove. That groove is called the intertubercular groove. It’s also called the bicipital groove, that’s because we have the tendon of the long head of the biceps that’s coming through here. We’re going to talk about that, of course, in a later video.
Another thing I want to point out about the greater tubercle is that we have three facets. You can see that here, we have the superior facet. Then, we have the middle facet, and the inferior facet of the greater tubercle. That’s going to come in handy when we to talk about some of the muscles that connect with the humerus.
All right. Some other things, right between the humeral head and the tubercle is where we find the anatomical neck. Just looking at it, it looks like the neck of the humerus and that just makes sense. This is the anatomical neck right between the humeral head and the tubercles.
However, we also have the surgical neck. The reason why we distinguish that is because this is a very commonplace of breakage. So, when we have fractures and broken bones, this is a very commonplace. This is why surgeon’s would refer to that as the surgical neck.
There’s one more structure that I want you to be aware of. That is the deltoid tuberosity. We have a tuberosity as we go more distal down the humerus, we have this deltoid tuberosity.
Now, before I move on, I just thought about something else to point out. Here, we have the greater tubercle, and it comes down, and we have what we call the crest of the greater tubercle which is this structure here, and the crest of the lesser tubercle. So, the crest of the greater tubercle, and the crest of the lesser tubercle.
Those crests, as I mentioned before this is the intertubercular groove, so this crest here, the crest of the greater tubercle, would be the lateral lip right here, the lateral lip of that intertubercular groove.
This crest here, that would be the medial lip of the intertubercular groove. That’s just for when we refer to some of the muscles once again that insert on, that will refer to the lateral and the medial lip of the intertubercular groove, and I want you to be aware of that.
So, let’s review. As usual, you can turn your volume down if you would like to test your skills and see how much you remember. So, here we have the head of the humerus. Here, we have the anatomical neck. This would be the greater tubercle, and this is the lesser tubercle. This would be the surgical neck. This would be the deltoid tuberosity.
This structure here is the intertubercular groove or the bicipital groove. On the greater tubercle, we have the superior facet, the middle facet, and the inferior facet. Right here , we have the crest of the greater tubercle, or the lateral lip.
Here, we have the crest of the lesser tubercle, or the medial lip of the intertubercular groove.
That’s pretty much it for this video. If you’d like to get more Biology resources to help make Biology fun, visit the website at interactive-biology.com.
This is Leslie Samuel. That’s all for now, and I’ll see you in the next video.