 coming to how I do it. This has been developed by our animation specialists who are trained by the IIT team and this will be put on the open source website. What I want to say is it is not a supine position with a slight head tilt. What I learnt from Winker Dolens is the more you tilt your head, the pyramid of the clientoid will become parallel to you. It is very important to have a frontal orbital psychomatic. We realize because I love cartoons and I think this is the best way to teach the crinotomy. So, then when you done the crinotomy and orbital psychomatic, this is the left side that is the frontal dura, that is the temporal dura, that is phenoid rich orbit that the phenoid rich has to be drilled down. So, you are actually here and this is what this is supine orbital pressure which is opened. That is the anterior clientoid process. Extradural drilling means you do not drill it like this. Extradural drilling means you have to cut the tentorial duplicature which is the meningo hypervisal band here or meningo orbital band which is directly coming down and while you are dissecting this, you are actually opening the pyramid of the anterior clientoid process. Then you are actually opening the supine orbital pressure. That is the foreman rotundum with the V2 and so, you are a clientoid which was covered like this has been opened like a pyramid. Then you can actually drill on as a surface of the pyramid. So, actually if you are here, you are actually drilling it right there. So, that is where you are drilling. You keep on drilling and that is the optic nerve, that is the optic knal being drilled. That is now the tip of the clientoid process. The rest is all drilled. This is just and with a diamond drill bit, you can shell it out. You can make a thin shell of a compact bone. You have to see a CT scan if there is no middle clientoid process present and with a sharp desector like flat desector, you can then like it is like a delivery of a canine tooth like a dentist does. That is something that you have to plan. That is how a clientoid. So, if you are not doing this procedure, you are in the anterior cavernous science mobilization, you will actually drilling it straight down and that can be very risky. Now, you come to the posterior part because that will be a part of my topic for the next presentation also, the anterior petrus. So, then you have the foreman's pinosum. So, foreman's rotundum was here. You drill the foreman's pinosum. That is the middle meningeal artery. You take off the middle meningeal artery and you expose it and cut it, divide it. That is the foreman's ovale with the V3 and you divide the middle meningeal artery there. So, again dilate in the foreman's rotundum, foreman's ovale, middle meningeal artery has been divided. The superior orbital fissure, you have to remember that the cavernous sinus is there are two walls. There is an outer meningeal layer and the inner membranous layer. This is the outer meningeal layer. This is the inner membranous layer where the fuse is at the nerves right where they enter these foramina at the foreman's rotundum, the foreman's ovale and over the vessels. So, if you try to divide it here, the meningeal and the membranous layer, you will actually enter into the dura. So, but if you are exposing these foramina down and you will actually see a junction where the nerve becomes, from a covered nerve, it becomes suddenly the sheath disappears. That is where you can give a sharp dissection and you can separate the outer meningeal layer from the inner membrane. That is the where you give the incision and where then you can strip the outer meningeal layer from the inner membranous layer. The membranous layer is covering the nerves. So, that is where they are covering the nerves. So, this is an extradural approach. You are nowhere opening the dura. It is all extradural. You can take, you can access the cavernous sinus, the peri-cavernous sinus. So, this is the gaseous ganglion. So, V3, V2, V1, that is the third, that is the fourth. The fourth is always anterior to it. It is lateral to the third nerve and then it crosses and becomes behind and reaches the tent. And that is the Parkinson's triangle between the fourth and the V1. That is always divided. Then we open the dura here. That is what we do. This is the part. We do not do this part, but we do the anterior cavernous part. Then we go for the clientoidal analysis. That is the division of the distal ring and the proximal ring. That is the falsiform ligament being divided. That is the distal ring being taken care of. That is the optic nerve, the ICA, the peak comb, that is the peak comb. That is the opposite third nerve. The ipsilateral would be here. That is the cavernous sinus. I will just take this off. That is the sixth nerve along with the intra-cavernous ICA. Then that is the GSPN. That is something which I will be talking about in the next session. We can strip the dura back behind the cavernous sinus. And this is where it is always stuck to the GSPN. So, if you do not do the sharp dissection, you are always in the injure the GSPN. Come back down. So, make it into a kavase triangle or a rhomboid. So, I will talk about that later so that we do not waste time in the next session. So, this is basically a continuum. That is the rhomboid bone which is devoid of any vascular structures. The ICA is here. That is the Glasgowx triangle, the Petrus ICA. Here in cadaver we always expose, but in real life we do not, we never do it now. That is the ICA. So, that is the posterior fossa dura and the middle fossa dura. So, you can actually, that is the sub temporal, the usual sub temporal approach, the tentorium, the posterior fossa. And you can communicate the middle fossa with the posterior fossa there. That is the main aim of the next lecture that will come to. That is the fourth nerve. So, you saw the fourth nerve in the cavernous sinus. You see the fourth nerve in the cisternal compartment and you are dividing the tentorium and you can see the PCA is on the brainstem there. That is opening the fifth nerve and that is the cavernous. We come to just two videos. That is a giant aneurysm, paraclylonal, communicating, incorporated a lot of stuff. So, that is what we are doing. You are stripping the, that is the temporal dura, opening the tentorial duplicature over the, over the anterior cliental process. So, if you drill directly here, you are actually, you may injure the ICA, also the aneurysm. So, you have to convert it into a pyramid. You actually drill along the long axis of the pyramid rather than at the tip of the pyramid. So, you are always in control. That is the optic nerve. Then it is the shell of the cliental process that is, that remains. When there is a giant aneurysm, there is some crowding there. So, you will have to do some sharp dissection. It always comes out like a tooth. Then we usually give a T-shaped incision in the dura, a normal thymic nerve along with open the falsiform ligament and the distal rings. That is the falsiform ligament. That is the optic nerve. That is the giant aneurysm. You can see that. We are intradural now. So, an extradural plus intradural. That is the ICA, a clip over the peak comb. Then this is the MCA, another temporary clip over the A1. That is the big giant aneurysm, coagulated. This was an elderly lady. So, this is semi-calcified. It takes long lot of clips to take care of that. So, even if you, when we ruptured it, punctured it, you need lot of clips because it becomes like a towel. You cannot just, with one clip you can never, like becomes a crumpled balloon. You can see that. It requires lot of clips, some fenestrated clips as well. So, the standard clipping is required. But a good thing about this extradural drilling is in these aneurysms, we do not do extradural drilling. Intradural drilling, you have to apply your clips like this, which is practically impossible if you want to do a reconstruction. Then this aneurysm has been clipped, the ICA, the A1, the peak comb. This is the last video. Another lady with giant aneurysm, paraclynoidal, very broad neck. So, this is on the other side. That is the left side. That is the temporal duora, the frontal duora. As you saw in the Kedavar specimen, that is the supra-optal fissure, temporal duora. You have taken off the, you open the supra-optal fissure. This is all extradural. This is the clinoid. So, if you do not open this temporal duplicature and mobilize the anterior cavernous sinus, you are actually drilling the ACP from the stem, which is wrong, which you can, you can have a good exposure, but you can injure the ICA and the aneurysm also. But this is what I learned from Inko Dolenz that if you mobilize a bit of anterior cavernous sinus and just take off the anterior duplicature right to the tip, you are actually going to see the complete length of the clinoid process to the tip. So, if the tip does not come last, the tip actually you are seeing all the time. You are actually drilling from the tip to the stem, tip to the stem, tip to the stem because under the stem, this will be the optic nerve and that will be the ICA. You can use the cutting initially, but then the solvice has to be diamond. That was the tip there and that was the stem and you will find that the optic nerve will slowly come here. That is the optic nerve here. The spinot sinus will be here. It should have drilled some more. This is slightly an old video. Normally, I drill, sometimes it breaks into pieces. So, now you have a temporal duora, frontal duora, similar in decision. The T-shape incision right till the base of the clinoid. So, it is a very small duel in opening. Only problem is, you have to close this, you have to put some fat pad underneath. So, still in fissure you are opening this tilling. So, that is the giant aneurysm with the ICA. That is the distilled ring. We can divide it right over the aneurysm, complete division. And here, when you start exposing that, you will realize that that is the A1, which is practically stuck. This has to be separated. If we do not separate that, it will come in the clip. That is the, this was a hyperplastic A1, but still we wanted to dissect it. So, then we realized that our optic nerve is still not free. Though this, she was blind from this side. We drilled this and we separated from the ICA. The MCA was free from the A1. You can always coagulate these aneurysms, always under cell line. You should have this section. You always have proximal control in the neck. You do not take any glass cocks, triangle control now. That is more of a problem later, because the eustachian tube there. So, the A1 is free. So, you can put a clip here, but what about the other side? So, we coagulated much more. So, then we started mobilizing here. That is the optic nerve. And then while I was doing this, something happened. That you can put a clip there, but we needed to mobilize some more, because the optic nerve is stretched. And I was separating and it ruptured. And I reviewed this video many times, but my scissors did not touch the aneurysm. I do not know how it died, but must have something, something. So, then some clips, but it always, it is always the surgeon's fault. So, what I had to plan it over the next 15 minutes, I had to do in the next 3 minutes. So, whatever clips you apply, still needs. Then you, here you have to take care of the pituitary stalk. That structure what you saw below was the pituitary stalk. So, that is the thing that you have to see in your craniopharyngeal mass or in hypothalamic amortemous. That is one structure that will always be visible in the groove between the optic nerve and the optic ocarotid system, the pituitary stalk that has to be preserved all the time. Your clips should never go and take them. This was partly from both. So, we have to dissect the aneurysm, so that it does not, that was well clipped. Just lost a cavernous hemangioma. And this is a hemangioma, which is right in the cavernous sinus. This is a pretty old one. So, the clinoid process is drilled. That is the frontal dora, temporal dora. Again, the clinoid is removed and the optic nerve is removed. This is the only tumor, which is in the cavernous sinus. There is no other tumor, which is only in the cavernous sinus, except for the 6th nerve sonoma, which is rare. But, that also bulges at one of the places. But, this is a homogeneous tumor of the cavernous sinus. So, once this is shelled out, then the form of spinosome is opened. It is very different in the cadaver. It is so clean there. And then, the middle meningel artery is divided. Then, there is the V3, the V2. Your main aim in this is, you have to remain extradurally. You should not go intradurally. What I am showing this is that, you may not be opening cavernous sinus ever in your life. But, yes, there are some tumors like the medial finoidic meningemus or even lateral ones who go towards the client. So, you are stripping the meningel layer from the membranous layer and all the nerves are within. These tumors should never be attempted intradurally. You will cut all the nerves before they reach the tumor. So, that is the V3, the V2. That is the superior orbital fissure being opened. And so, V1 will go here. So, that is the tumor bulge. Just imagine if you access this tumor intradurally and not extradurally, you will be cutting all the nerves like this. So, here you can actually see the nerves, the V2, V3, SN ganglion, third, fourth. And parallel to the fourth nerve, you open the Parkinson triangle there. We are always in control of the nerves then. Then, the only nerve which is now not left exposed is the sixth nerve. That will always be along with the internal carotid artery. A rapid decompression of such tumors. These are tumors that you have to be fast. You have to pray and you have to be lucky. Initially, I used to do. But now, there are two types of cannabemagemers. One, they cannot be shrunken because they are very friable. And those are the ones you have to. And now, you can see the ICA. And there is always a branch for meningo-hypophysiastrung and that is the sixth nerve. These are tumors that if you start coagulating and you are very sure that you will have six nerve and your sympathetic plexus will come in your coagulation always. And then, the tumors are always going to the cellar, always removed from there. You always lose two, three liters blood in these tumors. But the good thing is, the moment you remove it, bleeding stops. I do not know from how, but the bleeding stops. And then, the normal cavernous signs because then, you can pack it with some flow seal or surgical constant. When they were doing that, there was no flow seal. So, just constant for this nerve. So, thank you.