Okay. Knowing the spinal cord, the spinal nerve, there is a discussion, the third one today about two conditions that many of you probably have not suffered from but I guarantee 90% of you will suffer from that and let's discuss what happens with those. [FOREIGN] It turns out clinically where I worked. The age of onset for these two conditions is really really coming down with an alarming speed. We used to have people who are 60. 55 coming to our clinic and say, I have this problem. I have this problem. Now people in their 30s, or even in their 20s, suffer from these conditions. And it really, to the degree of having [FOREIGN], not just a little bit uncomfortable, but really, really a condition. So now let's use our knowledge of our spinal cord, of the canal in all of the several curves, and try to understand what happened to us. And the second question is, can we use the knowledge to make it better, for you and you? So my first question is, what happened? If you look at the structure of the bone. Of the nerve. What happened? If you notice that in the normal position, our bodies like an S shape right? This one itself is a spring [FOREIGN] so it can bounce with each other within itself. However if you do this, remember you have a very, very heavy head right here. Do you guys know how heavy it is? [FOREIGN] I haven't done that for myself, but you can at lease [FOREIGN] you know. It's very heavy. [FOREIGN] So if we stand like this, this heavy structure sits on top of this spring. But it's bouncing. It has a cushion. But if you sit like this in order for head not to drop, the back side has to really pull very hard. Right, otherwise we would go like this. So, the pulling, its constant that's eliminating this S shaped spring. That's why the, pathology wise, the disappearance of the neck spring is one thing we observe. And because of that distortion, [FOREIGN], our body is designed for that position. So the bones between the bones you have those discs. It's called intervertebral discs. [FOREIGN] It's between all sets of bones. So, that region has been compressed and compressed. There is a distortion. And when that happens the bone changes because our nerves are coming out from that. So it gets compressed. That's how you complain about not only the muscle pain, sometimes it's literally your arms are numb. [FOREIGN] Right. The same thing happens in the lumbar area. [FOREIGN] So our body is not designed to sit in front of a computer for eight hours without moving while you guys playing computer games. We don't do that. So that way you hurt your back muscle, number one. And later on it induces the changes of that. So if your two bones basically is like this, very good. And if you keep pressing like this so, the disk will slide to the direction where there is less pressure. Right? Always. So, [FOREIGN] and eventually it will impinge on the nerve. So, whenever that happens you have a shooting pain to that side from here all the way down. So, that's the typical cause of [FOREIGN]. These are the two really, really debilitating conditions that we have. The danger is we see that at younger and younger ages. Now for all of you who study Neurobiology of movement. So we want to do a good job in the class, but we also want to use knowledge to help you at least develop A healthy habit to prevent from developing these conditions at near future or in your middle age. One thing you do need to do is stand up and go around. Don't sit there for six straight hours. The second one is In your computer, if you can afford, get a bigger screen, okay. Get a bigger screen, the reason for that is, when these characters are bigger you can, you don't have to do this anymore. Instead you sit quite straight, right, you can be a little bit further away from the screen. That very simple thing, very simple. Now the screens are cheap, will rescue you from developing the two conditions at early age. And believe me, it will hit you if you don't take care of yourselves. Because our anatomy through millions of years of evolution was never designed for us to do things like this for hours and hours. Okay, so that's the practical usage of understanding the spinal cord and the spinal nerve coming from that. All right, any questions today? Burning questions?