 Good day everybody. This is Dr. Sanjay Sanayal, professor of the department chair. This is going to be a static demonstration of certain desiccant specimens of the spinal cord. So we have removed the occipital bone from here. This is the prone cadaver. We have done a posterior fossa craniectomy. So we have removed the floor of the posterior fossa. And then we continue down. We removed the laminate of the cervical vertebrae from the cervical thoracic, lumbar sacral coccygeal. And we also removed the paraspinal muscles. 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? This 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 and the sacral and the coccygeal nerves, which is referred to as collective with the cauda 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, which 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 cauda 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'm going to put the needle. So skin subcutaneous tissue. Supra-spinous ligament. Intra-spinous ligament of phlegm. You heard it, you felt it. This is exactly how you would feel. I'm sure I'm in the space. I have not removed the stilet yet. The moment you hear and feel the pop, don't go further anymore, even one millimeter, because then you'll go through. Immediately stop. And then you remove the stilet 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's 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 you do. Mandip has got plenty of CSFs with him. Okay, so we can collect the CSF for diagnostic purposes. And what is not given here to us in this model, there's a long burette, which is actually the spinal manometer. It's got a three-way stopcock. We can connect it here and we can read the pressure on the burette in millimeters of water. So that way we can do the spinal manometer, also, which I have told you in the class. And after the whole procedure, after you've 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 intraspanel injections of other agents, like for example, chemotherapy agents and all the rest of it. After the whole thing is over, then we have to reinsert back the stilet. This is an important point to remember. Many of you will try to remove the needle. You'll be so happy that you've got the CSF, you will immediately try to pull out the needle, reinsert back the stilet. And after you have done that, then the final step will be to put a thumb here, give a counter pressure of the skin. In other words, the skin will tend up and there may be a subcutaneous achemosis hematoma. We give the counter pressure of the skin here and pull the needle straight back. And after that, we put a ding chimp on C and you put the patient flat for 24 hours if necessary, lift up the foot end. So that's the procedure. Now let's see a few quick words about end of the spinal cord. End of the spinal cord is here. It is located in this region. This is referred to as the conus medularis. The spinal cord ends approximately the upper border of L2 vertebra and it is also referred to as the medullary cone. This conus medullaris, we can have an important syndrome here and that is referred to as the conus medullaris syndrome. That happens when there is any one of the intradural tumors like for example epindiboma, astrocytoma or we can have HIV lymphoma or we can also have arterial infarction of the region of the spinal cord. Incidentally, fracture of L1 vertebra. Can also produce the same syndrome L1 vertebra refers to this region of the spinal cord, which is the secret of the coaxial segments. When there is a compression of this region of the spinal cord, the segments which are involved are the S3 to CO segments, sacral third to the coaxial segments. Usually the manifestation will be suddenly non-sit and it'll usually be bilateral. Manifestations will be more severe pertaining to the parasympathetic portion that is the bowel bladder and male sexual mechanism, namely importance because the S2-3-4 segment is important for migratory center, defecation center and the male erection in the ejaculation center. So that is referred to as the conus medullaris syndrome. We can get another syndrome which refers to the portion above that and that is referred to as the epiconus syndrome, which extends from segments L4 to S2, which can also be caused by pretty much the same causes and the patient will have very severe difficulty in extension and lateral rotation of the hip joint because of the paralysis of the gluteus maximus muscle. Additionally, the person will have weak anchor jerk, which is root value is S1, S2. So that's about the conus medullaris syndrome and the epiconus syndrome. Now let's talk a few quick words about the cauda equinae itself. This cauda equina looks like a tail of a horse. That's why it is called cauda equina. The cauda equina can also be involved by medius tumors, intradural tumors. They can be nerve root tumors, lipoma of the cord, dermoid, neurofibroma and it can also be caused by HIV lymphoma and rarely it can be caused by a central herniation of the nucleus pulposus of the lumbar vertebrae. This is a T2 MRI of the spinal cord showing an HIV lymphoma in the region of the cauda equina. The cauda equinae syndrome usually occurs gradually and it is usually urilateral. Somatic symptoms will be more severe in the sacral saddle area. Saddle area refers to the area which a person sits on on a saddle and usually it is unilateral more common than it is bilateral so there will be severe pain and there will be muscle weakness in this region. So that is hemisaddle, anesthesia and hemisaddle muscle weakness. In contrast to the cauda's megalitis syndrome, the bowel bladder symptoms, the autonomic manifestations will be very few or very limited. There is yet one more condition which in this is not visible and that is called the phylum terminal. The phylum terminal is a neuroglial tissue which extends from the conus all the way down through the lumbar system and it then pierces the dural sac and it goes and gets attached through the sacral canal to the coccyx. That phylum terminal has got the internal portion. This is called the pial part and an external portion which is referred as the dural part. In a small person, the phylum terminal can be very short, thick and stout and it can pull on the lower part of the spinal cord and that is referred to as the phylum terminal syndrome. It can produce again symptoms pertaining to the lower part of the spinal cord that is the patient will have lower motor neuron bowel bladder symptoms and will have also have weakness of the sacral region, the weakness of ankle jerk. This same phylum terminal, if it pulls hard, then it can also produce traction on the upper part of the spinal cord and can produce downward displacement of the medulla through the ferrimid magnum and that is referred to as herniation syndrome. I had briefly mentioned that when I was talking about supra-intrural compression. So therefore, this condition is referred to as a tethered chord syndrome or the phylum terminal syndrome and it may require transsection of the phylum terminal. So these are the few quick points which I want to mention to you about the three regions that their clinical significance, the lumbar system, the corda equina, the conus medullaris and the phylum terminal. Thank you very much for watching Dr. Sanjay Sanyal Sanyal. If you have any questions or comments, please put them in the comment section below. Have a nice day.