 I can start to use this. It's got a digital meter which tells us the CSF pressure. This patient is in the lateral, left lateral recommend position and the touch and the feel of the mannequin is almost like that of a normal human this thing. So this is the spinal insert. You don't have to see what is inside and inside that there is this tube which contains the CSF, so-called CSF. So this is the actual spinal lumbar puncture needle. It's called the two-heed needle, T-U-O-H-Y. So this has got a hollow with a stillet inside and we have to put it with the stillet. Once we have punctured the dura and the arachnoid then you're supposed to remove the stillet and watch for the CSF dripping out. We are not supposed to touch this area because it's supposed to be sterile. So we are supposed to do the job with the holding the hub of the needle. And once we have done the procedure again put back the stillet and then take out it. Okay. So this is the iliac crest. Highest point of the iliac crest, highest point of the iliac crest. We made it very real lifelike. So when you join the two points then this is the supracrystal plane and when you feel all of you, you will feel that there is a spinous process here. So that happens to be the L4 spinous process. So therefore, just below that the space that my finger is dipping in, that is the L4, L5 space. And just above that where my finger is dipping in is the L3, L4 space. So you can do either L3, L4 or L4 to 5 and the one space above that there is yet one more space that is L2, L3. I'll demonstrate in several spaces for you. Okay. Now the procedure. Patient is in the lateral, left lateral decubitus position. The needle, of course, we have assumed that we have already painted it with iodine, povidone iodine, alcohol. We have put a drape with a central hole. We have put on gloves and even fit it in local anesthesia. So these steps have been taken care of. Let's assume. We are not supposed to hold this. Touch this area with our hand. So this is how I'm going to be holding and feel the spaces. We have already felt it. This is the space which I'm going to go through first. The plane of the needle should be exactly parallel to the ground surface. Absolutely parallel. And the direction should be slightly like this. This plane is parallel to this plane. But it should not be exactly at right angles. It should be angulated slightly like this. That's what I meant. The reason is because in actual human specimens, I'm telling you the right thing and the procedure because here this is a mannequin. They have made a small defect in manufacture. In actual humans, you were directed slightly towards the umbilicus. But in this case, I have seen that the umbilicus does not work because they have put the position of the openings in the vertebral canal a little obliquely. That's why I said it's a manufacturing defect. That's why you have to go a little in the opposite direction. Not like this, but like this. You get what I mean? So that's what I meant. Otherwise, the actual procedure in the human being is when you're going in, you're supposed to aim towards the umbilicus. But here we'll go slightly in the opposite direction. And you will get the feel exactly. You'll go through the skin, the subcutaneous tissue, the supraspinus ligament, the interspinus ligament, the ligamentum flavor, the extradiural space where you get the dirty tap. There is an extradiural space, but there's no blood. So you don't get the dirty tap. And after that, you'll get the combined urine, the raconoid. And you will actually feel the pop when you go through it. And you'll see it also when I go through it. All of you will be able to see it and you'll be able to hear it also. And that's exactly the feel you'll get. That's exactly the feel you'll get in a real life situation. And the moment you get the pop, when you feel it and you hear it, you stop immediately. Don't proceed even one more millimeter. Because if you proceed further, you'll hit the opposite side. Once you feel the pop, then remove the stillet. And you'll watch for the see-through dripping out. Now there are a few caveates on the process, during the process. One, we might hit bone. And as I'm doing, you might see that I might hit bone. Because the spaces between the spines process are very narrow. There's a reason why we flex the spine. Here we can't flex the spine. So you might hit bone. If you hit bone, don't try to manipulate. There's no way you can get past that bone. What do you do? Pull it out completely and reinsert again. Start afresh. That is the procedure to be done. So here also, if I hit bone, I'll do that. Next thing, once you have gone and gone into the dural space, sub-dural space and you felt the pop, I removed the stillet. Sometimes CSF may not come out. It actually happens. There may be a filament of tissue or something, some ligament or something is blocking the space, like those fimbria which are present inside the CSF space. What do we do? There are three things we can do. Two here, three in the patient. One is, just rotate the needle in its long axis like this. You might find the CSF will start coming out. That is one procedure. The other procedure is, take the syringe, attach it here and aspirate a little bit. That will remove the block and the CSF will start coming out. And the third procedure which you can do here, but which I said you can do in the patient is, ask him to go off gently. The moment he coughs, the intrastinal pressure increases and the CSF starts coming out. So these are the three things that we can do and two of them we will do here if we do not get the CSF in the first try. So supraspinus. I can feel the spinus process here. So this is the L4, L5 space. Exactly in the midline. Anesthesia has been given. So going through the skin, subcutaneous tissue, supraspinus, intrastinus, ligamentum flavum, you saw it, you felt it, you heard it. So this is the L4, L5 space. Now here we do not have that extra instrument, they did not give it with this whole set. There will be a 3S topcock with a manometer like this. So with the 3S topcock you can connect it here and you can record the pressure in millimeters of water. So the 3S topcock