00:01
Okay. So, now, let's have a look at the ulna.
00:03
We've spoken about the ulna and some of its
bony features when we looked at the elbow.
00:08
So, now, let's have a look at the ulna in a bit more detail.
It's medially positioned compared to the radius.
00:14
And it's one of two bones that form the forearm.
So, here, we have a look at the ulna.
00:19
We can see we have a proximal end, a shaft, and a distal end.
So, similar to that of the humerus.
00:25
And here, we can see some of those landmarks again
that we saw when we were talking about the elbow.
00:30
So, here, we have the anterior view.
00:33
We can see if we turn on the lateral view,
we can see the shape and the contours of it
and how it can sit in the olecranon fossa
and here, we have the posterior view.
00:42
Posteriorly, you can nicely see the olecranon here
and it's also highlighted in green on the lateral view.
00:48
And you can see that concavity created by the olecranon.
We can also see the coronoid process.
00:54
And that helps to sit on the coronoid fossa
when the elbow joint is fully flexed.
01:00
We can also see the trochlear notch
and that's the aspect of the ulna that articulates
with the trochlea, again, allowing flexion
and extension of this joint.
01:10
The radial notch is located on the lateral
aspect of the ulna
and this allows the head of the radius which is
circular in structure to actually rotate around.
01:20
Again, allowing pronation and supranation to occur.
Here, we have a bony prominence on the ulna.
01:26
This is the tuberosity of the ulna, allowing bony,
allowing the muscle attachment site to this region.
01:33
Now, we can see by introducing the distal
end of the humerus into this space
how the coronoid process can articulate
with the coronoid fossa.
01:41
So, we can see how we flex the elbow. We can see
how those two regions come into close prominence.
01:48
And here, we can see as we extend the elbow, how the olecranon
can sit in the olecranon fossa of the humerus.
01:55
Now, let's have a look at
the shaft of the ulna.
01:58
Here, we have an interosseous border and this is
important because between the ulna and the radius,
along this region, we have the interosseous membrane and that's
an important place again for various muscles to attach.
02:12
Here, we can see the anterior border of the ulna
and if rotated, we can see this posterior border.
02:18
This gives rise to an anterior surface, a medial surface, and then,
a posterior surface when we have it rotated around.
02:27
If we then go to look at the distal end of the ulna,
we can see we have the main prominent head
and also, a small piece that projects out
and this is the styloid process.