So here we have an example problem that wants us to rank the following joints in order from the least range of motion, which will label as number one to the greatest range of motion, which will label as number four. And then it wants us to predict how this would affect their ability to provide structural stability and support. And so notice that the four joints we're showing you here in this example are the shoulder joint, which of course is found in our shoulder, connecting the humerus to the scapula. And the sutures of the skull are also a joint. And those sutures are essentially these cracks that you can see in the skull highlighted there. And then we have the intervertebral joints which are found in our spine in our back. And then last but not least we have the knee joint, which of course is found in our knee. Now, in terms of the range of motion, we can go through each of these one by one. And in our shoulder joint, of course, our shoulders have quite a lot of movement and our spine allows us to lean forward and lean backward, which also allows for some movement. And of course, our knee joint allows for movement of our knee. However, what you'll notice is that the sutures of the skull, again, these cracks, essentially that you can see here highlighted in the skull are not very mobile. And so they do not have a great range of motion. They have very low range of motion. And so for that reason, they have the least range of motion of all the joints here. And we can label the sutures of the skull as number one for having again, the least range of motion. Now again, our spine does allow for some motion, we're able to lean forward and lean back. However, the range of motion of our spine is limited and it does not allow for as great of a range of motion as the knee or the shoulder, for example. And so the intervertebral joint is going to be number two in terms of the order or the ranking of the range of motion. And then the knee has less range of motion than the shoulder. And so for that reason, we can label the knee joint as number three and the shoulder joint has the greatest range of motion of all of these joints. And so, uh we'll label it as number four. And so now that we've ranked these four joints in terms of their range of motion, let's focus in on their ability to provide structural stability and support. And so recall from our last lesson video that there is an inverse relationship between the skeletal mobility of a joint and the structural stability of a joint. And so the greater one is the less the other is. And so the greater the range of motion, a joint has the less stable that joint is. And so again, the shoulder joint here has the greatest range of motion of these four joints. And because it has the greatest range of motion, it also is the least stable and that makes it more prone to injuries such as dislocations, for example. Now the sutures of the skull, again, these cracks that you can see here in the skull are uh are going to have the least range of motion here amongst these four joints. And so because it has the least range of motion, it has the greatest structural stability amongst these four joints. And that's going to be very, very important for the skull to have great structural stability because the skull plays a critical role in protecting our brain. And so, of course, we want to prioritize structural stability and support when it comes to the skull and protecting our brain. And so this here concludes our example problem and we'll be able to get some practice applying these concepts and learn a lot more about joints as we move forward. So I'll see you all in our next video.
