Hey everyone, in this anatomy lesson, I'm gonna cover the two bones of the forearm, the radius and the ulna. These bones are classified as long bones and they make up part of the appendicular skeleton. Now many people get these two bones confused, so let me begin by giving you a couple of memory tricks to help you remember which is which.
So first of all, whenever you hold your arm like this, as if you're gonna shake someone's hand, the ulna is always on the underside, so the ulna is under. And whenever you take a look at the elbow, That bony part of your elbow is actually called the olecranon process and that makes up the proximal end of your ulna. And if you trace that down you can feel your ulna bone.
Now when you hold your arms in the anatomical position, the radius bone is going to radiate out and away from the body. So it's going to be this bone right here on the lateral side when you're looking at it from the anatomical position. And an easy way to remember the radial bone is that your thumb is always going to be on the same side as your radial bone.
In fact, if you watched Nurse Sarah's video on checking the radial pulse, which is one of the most common pulse points used, by the way, she used my thumb as a landmark when locating the radial artery. Now let's take a look at the two forearm bones, and you'll notice that they have a web-looking connective tissue keeping them together. Kind of looks like these two bones just got in a fight with Spider-Man and Spider-Man 1. This is called the interosseous membrane. And the prefix inter-means between and osseous just refers to the bones.
So the name literally means the membrane between the bones. And this fibrous connective tissue consists of five ligaments, which not only help support and strengthen the forearm bones, but they also provide attachment points for some of the forearm muscles. Looking at the right forearm bones from the anterior or front view, let's examine the ulna first, which in the latin means elbow. And the good news is that you'll see some of the same names that you saw when we looked at the humerus because some of these parts actually fit together.
So first off, let's look at the olecranon process. And the word olecranon comes from a Greek word that means the elbow head. And this is a bony prominence that forms the elbow at the proximal end of the ulna.
And it allows for the attachment of the triceps brachii muscle. And if you watched my video on the humerus, you'll know that the olecranon process of the ulna fits into the olecranon fossa of the humerus when the forearm is extended. And the word process, anytime you see that word when we're talking about a bone, it just means a pointy growth or a pointy sort of projection coming off a bone.
Now the coronoid process is another bony prominence that is received into the coronoid fossa of the humerus during forearm flexion. And it allows for the attachment of the brachialis muscle. Between the olecranon process and the coronoid process, you have a large depression called the trochlear notch.
And this articulates or forms a joint with the trochlea of the humerus bone. And this is a type of hinge joint. And this hinge joint operates just like the hinge on your door. It's just going to allow it to go up or down like this.
Next, you have the radial notch. And this is a depression on the ulna that accommodates the medial head of the radius and it forms the proximal radio ulnar joint. And this is a big thing you've got to remember about the ulnar notch and the radial notch.
Their names are backwards. The ulnar notch is on the radius and the radial notch is on the ulna. That's one area where a lot of people get confused, so don't get those confused. Next you have the head of the ulna and unlike the radius, the head of the ulna is located at the distal end.
and it articulates or forms a joint with the radius at the ulnar notch, but does not articulate directly with the wrist bones. Next we have the styloid process of the ulna, and this is a small pointy projection that comes off the head of the ulna, and this provides an attachment point for the ulnar collateral ligament of the wrist. Now let's take a look at the anatomy of the radius, which is a latin word that means staff or spoke. And the proximal end or the top of the radius has a rounded cap looking area.
And this is the head and it has a depression at the top that forms a joint with the capitulum of the humerus bone. Now below any head you're going to have a neck. And this is where the radius begins to narrow just below or distal to the head.
Next we have the radial tuberosity. And this is a rounded projection that provides an attachment point for the biceps brachii muscle. Next we have the styloid process of the radius and this little pointy projection at the distal end of the radius provides an attachment of muscles from the forearm and hand as well as the attachment of the radial collateral ligament which articulates with the wrist bones.
Next you have the ulnar notch which is going to be a little depression in the radius which accommodates the head of the ulna and it's going to form this distal radio ulnar joint. which again is going to be a pivot joint that allows rotation of the forearm up or down. Okay, so that wraps up this anatomy lesson over the forearm bones. Now you can take a free quiz on our website by clicking the link in the description or at the end of the video. In addition, we have a whole anatomy playlist that we're going to be adding to over the coming months, so you might want to check that link out and see all the other videos we have on the bones and so forth.
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