This is a tutorial on the joints of the wrist and the hand. We’ll just take a look at some of the features of this joint and look at the ligaments and kind of movements that occur at this joint. We’ll start off with the wrist joint and we’ll work our way distally to the various hand joints.
This wrist joint is this joint here between the radius and an articular disc which lies at the end of the ulna and it attaches to the base of the styloid process. It’s between the radius and an articular disc at the end of the ulna and between the proximal articular surfaces of these three carpal bones – the scaphoid, lunate and triquetral bones.
The wrist joint is a condyloid synovial joint. You get flexion, extension, abduction, adduction and you get circumduction, which is a combination of all these movements. Abduction is movement in this direction. Adduction is movement towards the midline. Flexion and extension – flexion is up this way and extension is back this way.
It’s just worth pointing out that the styloid process of the radius actually extends further, extends more distally than the ulnar styloid process. This actually means that the wrist joint is more limited in its range of movement in abduction because the styloid process longer and it limits this movement a bit. Because of the more distal radial styloid process, the hand cannot abduct as far as it can adduct because the ulnar styloid process over here doesn’t extend so far.
The wrist joint is a radiocarpal synovial joint. It involves the three carpal bones here, the proximal carpal bones – scaphoid, lunate and triquetral. It involves the distal end of the radius and there’s an articular disc which lies over the ulna. It’s a radiocarpal synovial joint.
Let’s just quickly take a look at some of the ligaments in this area. You’ve got collateral ligaments. You’ve got ligaments connecting the radius and the ulna to the carpal bones, so you’ve got radiocarpal and ulnocarpal ligaments. And you’ve got ligaments on both sides. We’ve got palmar and dorsal ligaments. And then you’ve got ligaments at the end of the radius and ulna which connect these two bones together.
At the distal end of the radius and ulna, you’ve got this ligament connecting the bones on the palmar surface. This ligament here is the palmar radioulnar ligament. If I just rotate around and we look at the dorsal surface, you’ve got the dorsal radioulnar ligament.
Then we’ve got the collateral ligaments. We’re looking laterally at the wrist here and you can see a ligament connecting the styloid process of the radius bone to the carpal bone. This is the radial collateral ligament. If we’re looking at the medial aspect of the wrist, you can see the ulnar styloid process connects to the carpal bones, so this is the ulnar collateral ligament.
We can just see these ligaments here which run from the radius to the carpal bones and we’re looking at the palmar surface, so these are the palmar radiocarpal ligaments. Likewise, we’ve got palmar ulnocarpal ligaments. These run from the ulnar bone to the carpal bones.
If we just look at these in a little bit more detail, they can be broken down into two parts. The palmar radiocarpal ligament connects from the radius to the capitate bone, so this particular ligament is called radiocapitate part of the palmar radiocarpal ligament. And then you’ve got this other part which connects from the radius to the scaphoid and the lunate. This ligament is called the radioscapholunate part of the palmar radiocarpal ligament.
It’s the same with the ulnocarpal ligament, the palmar ulnocarpal ligament. It’s got two parts. One part connects to the lunate, so it’s called the ulnolunate part. And the other part connects to the triquetral bone, so it’s the ulnotriquetral part.
What you really need to take away from this part is just that there’s a radiocarpal and an ulnocarpal ligament and it’s on the palmar surface, so it’s palmar ulnocarpal and palmar radiocarpal ligament and they have two parts.
If I just rotate the model around, we can just look at the back of the hand and there’s only a radiocarpal ligament on the dorsal surface. There’s one dorsal radiocarpal ligament.
Those are the ligaments that you have at the wrist joint. You’ve got two collateral ligaments. You’ve got a radial and ulnar collateral ligament. You’ve got the two ligaments at the distal end of the radius and ulna. You’ve got the dorsal radioulnar and the palmar radioulnar ligaments.
And then on the palmar surface, you’ve got palmar radioarpal ligaments and palmar ulnocarpal ligaments, which are broken into those two parts.
And then on the dorsal surface, you’ve only got a ligament connecting the radius to the carpal bone. You’ve got a dorsal radiocarpal ligament.
Now we’ll just look at a few of the other joints that we have in the hand. After the wrist joint, we’ve got the carpal joints. These are the joints between the proximal and distal end of carpal bones. You can see that there are quite a lot of ligaments here, but there’s quite limited movement at this joint, but there is a little bit of movement and it helps to position the hand in abduction, adduction, flexion and extension. Those are the carpal joints between the various carpal bones.
Then next, we’ve got the joints between the carpal bones and the metacarpals. These are called carpometacarpal joints. You’ve obviously got five of these joints. You’ve got joints between the carpal bones and metacarpals and metacarpals 1-5.
The first one is a very interesting joint. This is the joint that made at the thumb. This is the joint between metacarpal 1 and the trapezium. This is a much more mobile than the other two joints between metacarpals 2-5 and the carpal bones. This is the joint between the trapezium and metacarpal 1. This is a saddle joint and it’s a lot more mobile than the other four joints.
You get flexion, extension, abduction, adduction and circumduction at this joint. There’s a little bit of rotation as well. It’s important to remember that this joint is particularly special and it gives rise to the mobility of the thumb.
The other four joints in comparison don’t really have that much movement. There’s just a little bit of gliding movements at these joints.
The ligaments, we have in this area, you’ve got palmar carpometacarpal ligaments and you’ve got palmar metacarpal ligaments. These are obviously the palmar surface.
If I flick over the other side, the dorsal view, we’ve got the corresponding ligaments, so we’ve got dorsal carpometacarpal ligaments and dorsal metacarpal ligaments.
Next, we’ve got these joints between the metacarpals and the phalanges. These are called metacarpophalangeal joints. These joints or condyloid joints and you get much more movements at these joints than the previous joints. At the metacarpophalangeal joints, you get flexion, extension, abduction and adduction. You can combine all these joints to produce circumduction. And then you’ve got a little bit of rotation at these joints as well. We’ll just take a look at some of the ligaments at this joints.
The metacarpophalangeal joints are actually quite straightforward. What you’ve got to remember is that there’s a palmar ligament. You’ve got medial and lateral collateral ligaments and you’ve got a deep transverse metacarpal ligament, which links the palmar ligaments together. It’s not actually demonstrated very clearly on this model, so I’m going to draw them on so that you can get a good idea of what I’m talking about.
The model here shows the joint capsule, but there’s a ligament here called the palmar ligament, which sits like this and connects the bones at the joint together. This is the palmar ligament. I don’t really need to draw every single bone, but I just have.
These palmar ligaments are connected by the deep transverse ligaments. You can see these ligaments connecting the palmar ligaments together. You’ve got three deep transverse ligaments. It’s important to note that there isn’t actually one between metacarpal two and one because this would really restrict movement.
And on the sides of the joint, you’ve got collateral ligaments. You’ve got medial and lateral collateral ligaments. Just to run through that again, you’ve got a palmar ligament. You’ve got deep transverse ligaments, which link the palmar ligaments together. And then you’ve got collateral ligaments and medial and lateral collateral ligaments. These help to reinforce the joint capsule.
Finally we’ve got the interphalangeal joints. We’ve got two of these. We’ve got a proximal interphalangeal joint and a distal interphalangeal joint. And these are really easy to learn about because they’ve got the same set-up as the metacarpophalangeal joint.
You’ve got the palmar ligaments, which sit like this. And then you’ve got the collateral ligaments which lie either side. You’ve got medial and lateral collateral ligaments. You don’t get as much movements at these joints. Obviously, you’ve just got flexion and extension. They’re simple hinge joints.
That’s the joints of the wrist and the hand. I hope that’s made things a bit easier to understand for you.