 Good day everybody. This is Dr. Sanjay Sanyal, professor of the department chair. This is going to be a demonstration of certain dissection specimens of the spinal cord. So we have removed the occipital bone from here. This is the prone cadabra. We have done a posterior fuzzacraniactomy and then we continued down and we also removed the paraspinal muscles. We removed the laminate of the cervical vertebrae from the cervical thoracic lumbar sacral coccygeal and thereafter we have split the dura to show the spinal cord. In an earlier dissection, we had mentioned the upper part of the spinal cord and the spinal nerve roots and many other features here. Now we shall focus on and we shall go right up to the bottom of this dissection to show you the lower part of this dissection. We have as I mentioned we have split the dura and the arachnoid and we have reached the lowest part of this dissection and this region that we can see here, this is referred to as the lumbar cistern. What is the meaning of the word lumbar cistern? Lumbar because it's in the lumbar region. It extends from L2 to S2, vertebral levels. Cistern means an enlarged subarachnoid space filled with CSF. What are the contents of this lumbar cistern? The contents of the lumbar cistern as I mentioned one is CSF. The second important content of course are these multiple branches that we can see here. These are the branches of the lumbar sacral and the coccygeal nerves which is referred to as collected with the corda equina. The third content of course will be a small structure which we cannot see which is a non-neural structure called the phylum terminale. This is the T2 sagetta labori of the lumbar vertebrae to show the lumbar cistern and its contents. Let's mention a few quick words about this lumbar cistern itself. This lumbar cistern as I mentioned it's an enlarged CSF filled space. Therefore, this is the ideal location for doing a lumbar puncture and CSF TAP for diagnostic or therapeutic purposes and I shall show you the demonstration of this lumbar puncture procedure in a short video clip a little later in this. We choose this area between L3 and L4 usually between the spinous process of L3 and L4 because here there is no spinal cord. Only the corda equina fibers are there therefore there is no risk of injury to the spinal cord and therefore this is ideally used for lumbar spinal TAP. So, in the next video clip you shall see the procedure of how this lumbar spinal TAP is done. I am going to put the needle. So, skin subcutaneous tissue, supraspinous ligament, intruspinous ligament of flavum. You heard it, you felt it. This is exactly how you feel. I am sure I am in the space. I have not removed the stillet yet. The moment you hear and feel the pop don't go further any more even 1 millimeter because then you will go through. Immediately stop and then you remove the stillet and you see the CSF dripping out. So, once the CSF you can collect the CSF for diagnostic purposes. Obviously, in real life you don't let the CSF drip out so freely because you will produce low pressure headache. Remember I mentioned it yesterday. So, that is why we have to put the patient flat and lift up the foot and all the rest of it. Here we can play around as much as possible. Mandip has got plenty of CSF with him. Okay, so we can collect the CSF for diagnostic purposes and what is not given here to us in this model there is a long burette which is actually the spinal manometer. It has got a three-way stopcock. We can connect it here and we can read the pressure on the burette in millimeters of water. That way we can do the spinal manometer also which I have told you in the class and after the whole procedure after you have done the diagnostic you want to inject drugs that is therapeutic you can inject local anesthetic agent to give regional anesthesia or you can give intraspinal injections of other agents like for example chemotherapeutic agents. We can inject radiopic diet through the lumbar puncture site and taking x-rays and that is called as lumbar myelogram as shown in this picture. After the whole thing is over then we have to reinsert back the stillet. This is an important point to remember many of you will try to remove the needle. You will be so happy that you got the CSF you would immediately try to pull out the needle reinsert back the stillet and after you have done that then the final step will be to put a thumb here give a counter pressure of the skin otherwise the skin will tend up and there may be a subcutaneous achemosis hematoma. Give the counter pressure of the skin here and pull the needle straight back and after that we put a tincture benzoin seal and you put the patient flat for 24 hours if necessary lift up the foot tent. So that's the procedure. That's all for now thank you very much for watching. If you have any questions or comments please put them in the comment section below.