 So let's start with the circulation of the cerebral system. We will see the arteries. We will see the veins. The brain, then you'll see the arteries in the veins of the spinal cord. Everything you've covered will not be in the information by tomorrow. And then we'll start with the later part of it. When we talk of the cerebral circulation, we divide it into anterior and the posterior circulation. The anterior circulation is the interrotate system. And the posterior circulation is the vertebral base in our system. And the two together unite at the circle of willness. So we will take them one by one. We'll first start with the anterior circulation. We'll see all the branches, all the relevant branches. We'll see their supply. Then we'll see the posterior circulation. We'll do the same thing. So let's start with the anterior circulation. Anterior circulation means internal carotid system. Parts of the internal carotid artery. Four parts. We are not so bothered about the first three parts, but we will just mention the names. Survival part in the neck. Not very important for us, except to remember that it has got a very arterial plexus. You can see the plexus in this picture here. This is the cervical part. Next part. Inside the peatress temporal bone. This is the peatress temporal bone here. So it enters like this. And you can see one opening here. It enters into the peatress canal. Therefore, you cannot see it. It is inside. This is the peatress canal. It comes anteriorly in the peatress temporal bone. It runs over this cartilage. And there's a foramen here. That's called the foramen lacerum. Which is the foramen lacerum. If you were to look closely, this is the foramen lacerum. That's where my point is pointing. Many people think that the artery goes through the foramen lacerum. No, it does not go through the foramen lacerum. It goes over the foramen lacerum. As you can see in that picture. Because the foramen lacerum in life is covered by a plate of cartilage. So it goes over the foramen lacerum. Once it goes over the foramen lacerum, now it has entered the cavernous signs. And it becomes the third part. The cavernous part. It runs in the cavernous part. We all know that it runs in many other structures. And it runs from posterior to anterior. In this portion. And as it runs, it forms a shallow groove on the side of the sphenoid bone. Which is called the carotid groove. Where it reaches the end of the cavernous sign as anteriorly. Just under the anterior plenoid process. Just under the anterior plenoid process. It makes a 180 degrees bend backwards. This 180 degree bend backwards is known as the carotid cycle. Please pay very close attention. And I will tell you more about it as we go along. And this is the place where it pierces through the dura and the arachnoid. And it becomes the cerebral part. And the cerebral part is the one which then supplies the brain. So three parts. Four parts. Cervical. Petrus. Cavernous. Cerebral. As I go along, you will find that throughout this chapter, I have mentioned certain things in blue. These are the clinically relevant parts. I won't be stressing them now because I'm going to talk about them tomorrow in great detail. But when you read, please pay very close attention to the structures marked in blue. Those paragraphs marked in blue. The carotid siphon is seen very clearly in radiological pictures. It will be seen as a vent like this. And this is a site of atherosclerosis. It is a site of aneurysm. And this is aneurysm which compresses on the lateral part of the optic chiasm to produce which type of hemianopia. These answers should come out as stats. It produces MC lateral nasal hemianopia. And I'll show you the relationship as we go along. So this is the importance of this carotid sinus. Okay, so now we have reached the cerebral part and now it divides into two terminal divisions, the ACA and MCA. And we shall see the branches of the cerebral part. That means after it has entered into the cranial cavity. Cerebral part. The branches of the cerebral part. The first and foremost branch, this is the carotid siphon. You can see there's a lateral view. There's an atropostria view. There's another picture to show you the cervical part, the pietrus part which you cannot see because it's inside the pietrus bone. This is the cavernous part and this is the carotid siphon. And you can see there's anterior trinoid process. So the carotid siphon is just infromedial to the anterior trinoid process. Are we absolutely clear? And once it is pierced through the diuretinoid, it has become the cerebral part here. Okay, branches of the cerebral part. The first branch. It runs just after the carotid siphon and this is the only branch which runs anteriorly. If you get this type of picture, you should be able to pinpoint it. This enters through the optic canal in orbit and in the optic canal it is accompanied by the CN2. And in the optic canal, it gives us the central retinal artery. For our purpose, that is the most important artery. And we have already seen the central retinal artery runs in the optic nerve and it supplies the neural layer of the retina. The story of the optic artery does not end there. The rest of the optic artery is distributed to the structures inside the orbit. It has got many branches inside the orbit. And it also comes outside the orbit and continues up as the supra-orbital artery. Which you would have studied in your anatomy. So that is the rest of the optic artery. But we are not bothered about that. I just wanted to tell you something very interesting. This is the only branch of the internal carotid which goes outside the orbit. Which goes outside the skull. That is the supra-orbital branch. Otherwise, all the other branches are inside the orbit. That is just for your interest. So the first branch is the ophthalmic artery. And we shall see many clinical correlations of this ophthalmic branch. We will see it tomorrow. Second branch. Take a very good look at this structure here. This is the section of the brain seen from the inferior aspect. And I have shown you this picture several times. This is the optic plasma here. And you can see the cut section of the internal carotid here. The second branch which comes out is the posterior communicating artery. This runs just about CN3. In the base of the skull. In the base of the brain, sorry. It runs in the base of the brain here. And it communicates with the PCA. That is why it is called the posterior communicating artery. So it runs in those proximal genes to CN3. This is the most common, second most common site of allurism in the circle of Willis. And when it enlarges, it can produce CN3 compression. Again it is mentioned there. Third branch. You can see very clearly here. And all of you know this branch. What is the name of that branch? Anterior choroidal branch. It runs just below the optic tract. It runs almost parallel and inferior to the optic tract. So therefore it supplies the optic tract. It supplies the NGV of the thalamus. It also supplies a little bit of the internal capsule. And it supplies, please take a good hard look at this. It supplies the choroidal plexus of the actual ventricle. So this is the supply of the optic of this choroidal branch. And we have already seen some clinical correlations. Can anybody name that clinical correlation for me? Occlusion of the anterior choroidal artery produces something called olacosynryl where you have contralateral homodimus immunopia because of lots of blood supply to the optic tract as well as you can see the NGV here. This is the lateral geniculate body. This is the beta geniculate body. You can see that. And it also supplies. So therefore this portion, this anterior choroidal artery has got two segments. A portion which supplies the choroid plexus that is known as the plexus segment and a portion which is running in this cistern of segment. That is the interpreter of the cistern. So this is the third branch. And finally the rest of the interporotate divides into its two terminal branches. A small ACA and a big NCA. Now we shall take these one by one. The ACA, the first one, the smaller one. The smaller of the two terminal divisions which runs antero-medially just above the optic nerve. Just superior to the optic nerve. These are two optic nerves. It goes antero-medially and it enters the longitudinal fissure of the brain. The longitudinal fissure. The moment it enters the longitudinal fissure of the brain it is joined by, from the opposite side by one small communicating branch who will take that branch for people. Small communicating branch is the ACA anterior communicating artery. And you can go and have a look at the relationship of the ACA to come to the optic hyacinth. This was a question in your block 3. The ACA is situated just superior to the optic hyacinth in the upper part. It's a very small branch but this is the most common site of aneurysm inside the cell openness. The second most common was the ACA or ACA is the most common site. It is joined by the ACA. Let's continue with the other branches of ACA. So it is joined by ACOM just above the optic plasma here. The rest of the ACA then runs all around the corpus callosum. Most of the ACA runs around the corpus callosum like this. The portion of the ACA which is similar to the ACOM it is referred to as A1. And the portion of the ACA which is distilled to the ACOM that is the rest of the ACA is referred to as A2. And there are many other subdivisions. A3, A4 is not bothered about A3s and A4s. For our corpus we will remember that the portion of the ACA proximal to the ACOM is called A1 and the portion distilled to the dist is called A2. Why are we bothered about this subdivision? Can anybody hazard a guess? You will know about it tomorrow but I would like you to take an answer. The reason is if there is any occlusion of the ACOM there will be collateral circulation from the other side. There will be no hysteric management issues. On the other hand, if there is an occlusion of the ACA distilled to the ACOM that is A2 onwards you will get anterior cerebral artery occlusion symptoms. Make sense? That is the yes. Approximal means before the ACOM that is this. This is proximal and this is distilled. This is proximal and this is distilled. Make sense? So if the ACOM is somewhere here, this portion is proximal and this is distilled. So just think of any structure which is flowing. The one upstream is called proximal. The one downstream is distilled. So any occlusion before the ACOM is there will be no symptoms because if it is distilled to the ACOM then A2 onwards is really simple. That is the reason why we have subdivided ACOM into ACA to A1A. Continuing with the ACA it continues over the genu rostrum and the genu and the body of the corpus callosum till the anterior forks. These values are very important. And then in astromosis with the branches of PCA which we shall see a few slides later. So this is the course of ACA. Again, there is an important point here. When it is going over the corpus callosum like this, this curved portion it is one of the very common sites of atherosclerosis and we shall see tomorrow why so. Just more in the red and blue. This is the common site of atherosclerosis. This is another picture to show you the same thing. And it in astromosis somewhere here with the branches of PCA. So this is the course of the ACA. Now let's take the branches of ACA. Overfills of the corpus callosum. When we talk about the branches for all these ACAs ACAs, MCAs and PCAs we are going to talk about two sets of branches. One set of branches are called the cortical branches and the other set of branches are called the cortical branches. So we will not repeat them again and again. We will automatically take it for granted that all these cerebral arteries have got cortical branches and cerebral branches. Let me tell you what does it mean. Cortical branches means they supply the outer few millimeters three to four millimeters of the gray matter that mortgages. That's what they call cortical branches. Central branches means they supply the deep sub-cortical structures gray and white. So that's what the meaning of the central branches and versus cortical branches. So let's take the cortical branches of ACAs first. I have written a few names there that just for your amusement don't memorize those names. The cortical branches are the ones which are seen in this picture and it's also shown in that picture. ACAs supplies most of the medial surface of the cortics, the cortical branches. Therefore, it supplies the anterior, almost the entire cingulate gyrus. It supplies the medial frontal gyrus. It supplies the paracentral lobule. Paracentral lobule, if you remember is the indentation seen on the medial surface by the central sulcus of Rolando. It supplies up to the pre-cunius. It supplies the medial PFC and it supplies the orbital frontal PFC. Medial PFC is this surface and orbital frontal PFC is this surface. So these are the cortical branches it supplies. It does not go beyond the paracentral surface. As you can see very clearly here. So remember here is the artery for the leg area of the cortics. And all of us know that the medial surface of the cortics is concerned with the leg area. Of course, there are many other structures of this area. You shall see them in a couple of functional areas. Right at the beginning of the ACA just after the ACA it gives out a small curving branch. You can see this one here. This has got a very important function. This is called the recurrent artery This is also called the recurrent artery. It is also referred to as distal medial spied artery. What does it do? I have to tell you guys. It is a recurrent artery. The rest of ACM is going in this direction. This is going in the reverse direction. That is why it is called the recurrent artery. It is also called the medial and spied artery. So look at these words. What is this one? This is small artery. It supplies the medial surface of the PFC and it also supplies a little bit of the spied artery. Anti-abotable spied artery. That is why it is also referred to as distal medial spied artery. This has got a very, very important in the correlation which I shall not talk about now. Just do not look at that. So these are the supplies of the ACM. It is an artery of the medial surface. However, what is not shown in this picture but I am going to show it in another picture is that same ACA also supplies a little bit please look at this very closely. It supplies a one inch strip of the cortex of the supralateral surface also. So not only does it supply the medial surface, it extends a little bit onto the supralateral surface at the supralateral margin. That is an important point to note. I will show it in another picture. So these are the cortical branches and it is written there also. Coming to the central branches the central branches are these branches here you can see in this picture. These are referred to as anglomerial central arteries because they are coming from the anglomeria part of the supralateral but they are all branches of ACA. These are very special branches. Look at this. We penetrate the surface of the cortex at right angles through an area of the cortex here shown which is called the anterior peripheral substance that area of the brain is called anterior peripheral substance because it is perforated by these branches. Next steps. Anglomerial central arteries are the ones which penetrate through this area and this area and enter into the substance. Now these arteries are the end arteries. They are end arteries. They do not last the most inside the substance of the brain. And these are sites of occlusion and produce a special type of infarction which are known as lacular infarcts because they are end arteries that do not last the most and they have a lot of problems. We will talk about it tomorrow. So these are the anterior media central arteries which are the central branches. They are perforating arteries because they perforate. They perforate through the anterior perforated substance and they are end artery that do not last the most. What do they supply? They supply all the structures in the depths of the cortex and which are they? You will mention a few of them. They supply the anterior part of the basal ganglia. They supply the anterior limb of the internal capsule and they also supply especially this this branch that this main artery that you see here this is called the pedicelosal branch. They supply the anterior perforates of the perforated cellosum. So the central branches are the ones which supply these important structures which are required for us. Anterior perforates of the CC is supplied by ACA. Anterior limb of the internal capsule is supplied by ACA and anterior part of the basal ganglia is supplied by ACA. So these are the anterior perforating central arteries and they perforate through the anterior perforated substance. Now let's come to this. This is the summary slide of the ACA and it pretty much recaps in brief one slide. What are we going to do? The important point to be noted here is that what we do is supplies the leg and the foot area for the body. Both sensory and motor. The anterior part is motor and the posterior part is sensory. All of us know that. And it also supplies the medial frontal gyrus. Medial frontal gyrus controls the urinary sphincters, if you remember. And of course it supplies the radial BFC it supplies the orbital frontal BFC. And of course it supplies the anterior perforates of the perforated cellosum. So ACA leg and foot area as a good memory for you to remember. And we shall see the significance of the recurrent artery of the urinary sphincter. A little later, maybe tomorrow we'll talk about it now. Now let's come to the larger of the terminal branches of ACA of the intracarotid, the MCA. We have already seen the picture, the first picture where the MCA ran like this. So the MCA, once it starts from the intracarotid, it runs laterally. Just for your recollection, let me show you this picture so we can see that this picture runs through there. Can you see the MCA running laterally? The MCA runs laterally. It runs in the lateral picture. Why does it have to run in the lateral picture? Because it has to run through the lateral picture and it has to run from the inside, it has to run through the lateral picture and it has to come outside there. That is why it runs through the lateral picture and then what you see here is how it has come outside through the lateral picture. So it runs laterally through the lateral picture and comes outside. So it comes out in the depths of the lateral picture. It comes out from there. Okay. In the depths of the lateral picture, there are many things happening. It divides it into two principal trunks, superior trunks and inferior trunks. Take a good hard look at that because that is, again, a very common side of a few roasts. The superior trunk comes out of the lateral picture and it supplies the supral lateral surface of the cortex. Not the lobe and the lateral lobe. But we come to that later. The inferior trunk, again, comes out through the lateral picture and supplies the infral lateral surface of the cortex. Predominantly there. So this is the course of the MCA. Now let's take a look at the branches. Again, same thing. Cortical branches. Cortical branches. It supplies the entire supral lateral surface of the cortex. As you can see this picture and this picture, you can see the artery coming out here. But it does not supply three areas. Yes. Sir, if you saw that point, you said that the ICI also does a one-inch spanner. I'm not into that now. It supplies the entire supral lateral surface of the cortex except three areas. One-inch tip on the cortex here. Can you see? Because that is already supplied by AC. Next, it does not supply the inferior temporal virus. Because we shall see that it is supplied by AC. And it does not supply the occipital lobe. The cortical branches supply the entire supral lateral surface except these three areas. Yes. Sir, can you see that point? Will I ever converge or does it ought to be very far? There is a very... Here, the arteries are... I'll come to that about 15 slides later. Your question will be answered a little later. So this is the supply. This is the distribution. There is a cortical distribution of the MC. Regarding the conversion in the artery business, I'm going to come to that just a little later. So you can clearly see the distribution of the MC. So, point to be carried forward. MC has supplied the bulk functional areas of the cortex which you have all studied. And I have reproduced them here for you. First, it supplies the both motor and sensory, the face and arm area. Yes or no? MCA is the artery for the face and the arm area. Both motor and sensory. It supplies the premotor cortex. It supplies the frontal IT. It supplies the brocasse area. It supplies the verdict case area. It supplies the primary and the secondary auditory areas. So these are the important functional areas that we need to remember. I'm going to show the functional areas from the clinical picture tomorrow. But right now I'm mentioning them because you have to know them. But not forgetting, it also supplies the superior parietal lobeul and the inferior parietal lobeul of the parietal cortex. What it does not supply is it does not supply lobeul. So if you have already mentioned, so it stops there. And it does not supply the inferior temporal gyrus. So this is the supply of, the cortical supply of ACA. Please remember the functional areas. Therefore, verdict case A-P-A-C-R, brocasse A-P-A-C-R, motolipene, motor cortex of the arm, face, all the things, auditory cortex regions, everything that you studied are all MCA occlusion strokes. Makes sense? So these are all the MCAs. So MCA is the face in the arm area. To continue with our story, the central branches of MCA, as we have already agreed, central branches are those which penetrate into the cortical substance. We also do the same thing. Take a look at these branches. This is the course of the MCA. As I told you, it is running laterally through the laparofisher. This is the coronal section of the brain. This is the coronal section of the brain. You can see the laparofisher here. It runs like this and comes on the surface and we have described this supply. We have described these supplies just now. Now I am talking about the central branches. To show you the central branches in another location, let me take a picture of this one. Can you see the MCA running here? Can you see these branches coming out? Small small branches. They are the same branches here. They are called the angiolateral central arteries. For the ACA, we have called angiolateral central arteries. Here they are called angiolateral central arteries. They are the penetrating endartics. Let me get out of this picture and come to this. These are very important. They are so important that I can even emphasize them. They are so important. They are called angiolateral central arteries. They are also called latitoral stride. They are also called charcoals arteries of cerebral hemorrhage. 90% of the strokes that you will see and trust me you will see even whether you are a neurologist or a neurosurgeon or not, you will see many more chelopracties are caused by these arteries. These are the angiolateral central branches called latitoral stride arteries. What do they do? There are two sets of these. There are many of them. There are hundreds of thousands of them. As you can see in these pictures, they are divided into a middle group. The middle group supplies the inner part of the stride and the trissel ganglia. And the lateral group supplies the lateral part of the trissel ganglia. So they have been just for the sake of understanding, they have divided into a middle group of stride arteries and lateral group stride arteries. This is the major part of the trissel ganglia. So they are all branches of antrilateral central arteries also known as latitoral stride arteries. They are all serotoninous. Also known as charcoals arteries of cerebral hemorrhage and we are going to talk about this in great detail tomorrow. Okay, let's continue. These ones, these are like the bulk of the trissel ganglia. The ordinary nucleus would have been chelopospiritis. And they also supply Please don't down and write it down hundred times. They supply the genu of the corpus callosum and the posterior limb of the corpus callosum. They supply the genu and the posterior limb of the corpus callosum. In the temporal lobe, they also, the central branches also supply, do we remember, do we remember a part of the optic radiation which found a loop into the temporal lobe and then one went backwards. Let me give the name. Myerzo, the media and the MCA branches. Central branches also supply the Myerzo. Yes. Oh, I'm so sorry. I'm so sorry. Please forgive me. Yes, they supply the genu and the posterior limb of the internal gas. It's about 90% of the gas. I sometimes, I get carried away with my own goals. They supply the genu and the posterior limb of the internal gas. So these are the central branches that you can see very clearly. We will come back to these branches with clinical correlations and I'm ordering a new date to it. I'll tell you in detail about them tomorrow. So this is, again, a summary slide of the MCA and pretty much details whatever we have mentioned. It supplies the base of the area of the cortex. It supplies most of the functional areas that we have studied in the cortex. It supplies the genu and the posterior limb of the internal capsule. There's another picture to show you all the functional areas with the MCA distribution. Do remember that it does not supply these three strips of cortex. One here, one here, and one here. It's, again, another picture to show you the same thing which you have mentioned. The reason why I put 20 pictures and all these things is so that you are absolutely clear, clear picture in your mind in order to memorize things. So we have finished the anterior circulation. What was the anterior circulation? Now let's come to posterior circulation. What was the posterior circulation? The vertebro-basular system. So just for your recap again, this was the anterior circulation which we finished. Now we are talking about the vertebro-basular system. We will break it up. We'll first take the vertebral artery, then we'll take the posterior artery, and then we see the branches. Vertebral artery. Again, four parts, respectively, called V1, V2, V3, V4. We will not bother our heads over all the parts except the relevant serine points. The V1 is the cervical part. It runs in the neck. It runs through all the muscles in the neck and all this goes through the triangular space. Second, V2 part, the vertebral part. It runs through the transverse part of the cervical vertebrae. That's actually called the vertebral part. If you remember that you run at me at the cervical vertebrae, the transverse process has got small openings. They are called the transverse pormen or the pormen transverse area. So it goes through the transverse pormen of the cervical vertebrae, starting from the C6 upward, C6, 5, 4, 3, 2, 1, not the C7. The C7 pormen transverse process either does not have a pormen or if this pormen is very small. So it goes through 6, 5, 4, 3, 2, 1. That's the vertebral part. And here, this is very important. You will see, may see, that you will see a lot of excessive vigorous survival manipulation. Like sometimes it is done by higher practitioners catch hold of the group 10 and those vigorous manipulation like that. No, I'm not going to do this. I'm just going to do some work with you. Yeah. Could use rupture of the tunica intima of the vertebral arteries inside the vertebrae. That's the pormen. And then the tunica intima structure, that goes into the tensile media produces a function which all of you know or is dissecting it. It is not a theoretical thing. It is a well-documented dissecting aneurysm of the vertebral artery can occur from excessive vigorous manipulation of the cervical spine and it occurs in this segment. Third segment. It goes through a small triangle at the base of the skull it goes through a small triangle and then it will create the atlantic occipital membrane and it becomes the cranial part. The cranial part, so the suboccipital triangle is here. It pierces through the atlantic occipital membrane and enters through the, that is the cranial part. And that is the one. The cranial part, it runs anteromedically through the pormen magnum in front of the medulla. Medulla, as you know, runs through the pormen magnum. Medulla is running through the pormen magnum. So it runs anteromedically from both the sides in front of the medulla. It runs in front and it unites at the lower border of the pons. It becomes the venus in our artery. Again, the site of union of the two vertebral arteries is a very common site of materials in the posts. We will continue with the basilar artery just after we have finished with the branches of the vertebral artery. So this is the component, the parts in the pose of the vertebral artery. The branches of vertebral artery. We are concerned only with the cranial branches. We are not concerned with the branches in the neck. The vertebral part does not have any branches. Some of them also do not have any significant branches. So this is the portion which has already entered the cranial cavity. And you can see it is running anteromedically in front of the medulla. And it unites at the lower border of the pons to form the basilar. So let's focus on the branches of the vertebral artery in the cranial part. First, it gives rise to the two posterior spinal arteries, which is not clearly seen in this picture. Two posterior spinal arteries, they run in relation to the dorsal root of the spinal cord. You will see it in great detail at the end. It also gives rise to two anterior spinal arteries here. It gives rise to the two anterior spinal arteries, these two anterior spinal arteries, and they form a single anterior spinal artery and it runs in anterior medial fissure of the spinal cord. And we will see this also in great detail at the end of this chapter. Third branch. All of you know this very well. We have talked about it several times. Can you see this big branch coming out here? This long one. Who will lend this for me? This is the pica. Posterior, inferior, cerebellar. This supplies the dominant part of the posterior inferior part of the cerebellum. And it also supplies the natural part. We have already seen the conclusion of this pica. This is what is known as that. It's syndrome. Natural, yes. Warren Berg syndrome or natural medial syndrome. We will repeat all those symptoms again. So this is the pica. Next, what is not shown here, the vertebral artery gives us the humerus unnamed medullary branches. These medullary branches are subdivided into paramedian branches and third-term friendship. These are also improved because they produce both the medial medial syndrome as well as the lateral medullary syndrome. They are the unnamed and finally it also implies to compute meningeal branches. This supplies the meningees of the posterior cranial also. The same point is mentioned in the meningees chapter also, just in one line. So these are the important branches of the vertebral artery to cranial part. Again, I'm telling you when you're reading them, please take a good hard look at the blue portions and do a special note of it. Now let's come to the basilar artery. We have already seen the two vertebral arteries uniting at the lower border of the pons to form the basilar artery. So let's take the course of the basilar artery. The basilar artery runs in front of the pons. Here. It runs like this. So remember, the vertebral artery is ran anterior medullary in front of the medulla. And the basilar runs in front of the pons, anterior to the pons. In an actual situation, the skull is somewhat like this. So the pons is resting on this sloping bone here. This sloping bone is the clivus of the occipital bone. So the basilar artery is situated between the pons and the clivus. So the basilar artery runs between the pons and the clivus. On the entries of the pons, there's a shallow groove. Now you know that that basilar groove is filled with C-S-F, and that is called the pontine cistern. I mentioned it yesterday. So the basilar artery runs in the pontine cistern. In anterior to the pons, between the pons and the clivus. At the upper end of the pons, in the region of the midbrain, it divides into its two terminal branches. The pcs. So this is the course and the relation of the basilar artery. Now let's take the branches of the basilar artery. All of them are grand daddy branches. Each branch has got a syndrome associated with that. And all of you go with the syndrome. Yes. So I took my one thread, and now I'm right here to the bottom. The 5-meters directly into all the brain circles. Yes. The basilar artery runs on that. Exactly. That's the system. So as you know, the subarachnoid system is the 3-meters and the basilar. Yes. So it is running into the two. All the basilar artery runs in the subarachnoid space. Here it is called the subarachnoid system. It's called the pontine cistern. You're right. It's running into the basilar artery. Absolutely. Okay. So let's take the branches. And all of the branches use syndrome and we know the syndrome. Let's start with the lowest branch. The first branch. The branches we count from below up. One, two, three, four, five. The first branch of the basilar artery is this one. This is lateral view. This is the WCVF. The AICA. Antidrain clear cerebellar artery. So the antidrain clear part of the cerebellum. The previous one was BIC. This is the AICA. Antidrain clear cerebellar artery. One of these produces lateral, inferior, pontine syndrome. Next. Just after that. Now please follow me very closely. I know a few of you have been very close attention, but there are so many clinical correlations that I have to go step by step. Just that, after that, the second branch is coming out. It's a very small branch. Labyrinthine. What does this do? Between the AICA and the labyrinthine artery, can you see one cranial nerve emerging? What is the cranial nerve? CN6 is emerging. CN6 can be compressed by aneurysm of the AICA. CN6 is compressed by aneurysm of the AICA. Let's continue with our story. When the pause is running and the pontine system, this portion, this portion, it gives us to numerous unnamed branches. You can see all of them here. It gives us to numerous unnamed branches. These are known as the paramedian pontine branches. These are also penetrating aneurysms. They authenticate into the substance of the bonds. And the media goes part of the bonds. A portion of them produces yes, complete the sentence. Okay, CN6, 5. Width syndrome. Medial pontine syndrome. Because it's running right in the midline, media pontine syndrome. CN6 is in world truth, but I want the name of the syndrome. Medial pontine syndrome and the infarction produced by these are known as lacular infarctions, again, because we are all penetrating aneurysms. You start getting used to these words, lacular infarctions, because tomorrow we are going to talk about the next great detail. I'm going to show you pictures also of lacular infarctions. So these are the paramedian pontine branches. They supply blood. What are they produced? Medial pontine syndrome. Then, just in the upper part of the bonds, it gives us the second-large branch. SC, superior cerebellar artery. Superior cerebellar artery. This supplies the upper part of the surface of the cerebellar and also some lacular part of the bonds. Occlusion of this will produce, again, lateral superior pontine syndrome. This is lateral superior pontine syndrome. Continue with the story. Take a good look at this. The SCA runs very close to this nerve here. What is the name of this nerve? This one. It runs very close to the type. Sometimes, a redundant loop of this SCA can compress from the sensory division of the vaginal nerve. What is the sensory division? And it can produce a syndrome. What is the name of the syndrome? Trigeminal nerve. How it produces. It runs very close to the trigeminal nerve. So, we have already seen two clinical correlations of this SCA. Finally, at the lower level of the mid-brain, the PCA is the basal artery device in which two vaginal divisions, the PCA and the alpha of the PCA in brain detail. So, between the second-large branch SCA and the last-brand PCA, again, you can see an artery now coming out. What nerve is that? So, we have seen the branches of the basal artery and its relationship and all this. Now, before we come to the PCA and its distribution, let me tell you the blood supply rule of the brain step. This is again going to be two slides, are going to be repetition of what we have already seen in block 2. But I will repeat it again for you. Take a look at these pictures. The rule is written here, the picture is shown here. This is a random section up once at three different levels. The same principle applies to the medulla, the same principle applies to the midbrain. This media portion colored violet is the paramedian branches. I am going ahead of the process, sorry. Let me go step by step. Rule number one, the artery for the medulla is the body. The artery for the pawns is the basal artery. The artery for the midbrain is complete the sentence. The PCA. That is rule number one. PCA also supplies the body. If we should see just how that is. He says supply is also a little low. Yes, we know that. But it also supplies the midbrain because it is a branch in the front region of the midbrain. The PCA supplies the midbrain also it supplies the body. So please get this point clear. Therefore, the PCA occlusions will produce both midbrains in robes and it will produce cortical syndrome. This point should be clear to everybody's mind. So that is rule number one. Rule number two, each of these arteries, vertebral on-time and basilar and PCA may give rise to a series of named branches and a series of unnamed branches. The named branches we have already seen. We have just mentioned that. What about the unnamed branches? The unnamed branches are again divided into two sets. A series of branches which are given off immediately in the midline near the midline. They are called the paramedial branches. And it gives out a series of long branches which go all around the brain. They are called the circumferential branches. Some of them are short, some of them are long. That is rule number two. The paramedial branches they supply the medial part of the brain stem respectively, medula on slippery. The circumferential branches the short circumferential and the long circumferential, the short long, short long. They supply the ventrolateral parts of the brain as can be seen in these color coded pictures. So what is the significance of this supply? The significance of this supply is the paramedial branches which supply the medial part of the brain stem they contain most of the finished sentence. They contain, they supply most of the motor structures, most of the essay. There will be exceptions. Mostly motor structures. While the circumferential branches, the short and the long by the ventrolateral and the rossolateral parts they supply mostly the censored. And finally occlusion of these paramedial branches will produce all the medial syndromes. Medial medullary syndrome apart from the named branches which we have already finished even these will produce the same syndromes. The medial medullary syndrome, medial quantum syndrome, medial medullary syndrome. By the occlusion of the long branches sorry the circumferential branches will produce the lateral syndromes. The lateral medullary syndrome the lateral quantum syndrome and there is no lateral medullary syndrome but there is a paramedial syndrome. So occlusion of the named branches will also produce syndromes but occlusion of these unnamed branches will also produce the same syndromes. This is the rule of the blood supply of the brain stem. I have written these rules so that you can remember them with these pictures. Now let's see the rest of the PCA that you finish this PCA and then we take our brain. The rest of the PCA after you supply the mid brain you supply the mid brain by means of the paramedial branches and the circumferential branches get done with it. The rest of the PCA I'll tell you the course of the PCA because that's very important for us and I'll tell you the distribution of the branches. So if you look at the same picture which you are familiar with this is the section of the mid brain yes or no? You can see that bit of the syllabus you can see the cross cerebrae and the cerebral peduncle is there. This is where the PCA started from it started from the level of the mid brain remember as a terminal division of the PCLR it winds around the cerebral peduncle like this this is the cerebral peduncle and you can see it is winding around it is shown in this pictures it winds around the cerebral peduncle like this from front to back a very common side ethereal sclerosis the bifurcation of the basilar artery to two PCAs is the side of aneurysm and the curving around of the PCA is the side of ethereal sclerosis so why are these sides of ethereal sclerosis? I'll tell you the whole this is the common side of ethereal sclerosis and once it winds around it is joined and then the first side here what was that? the PCOM so again the portion of the PC approximate to it and the portion of the PC distributed to it has got two different segments the portion approximate now you have understood this is proximal isn't it? proximal one it started from this is what happened there proximal part is for p1 and this part is for p2 y same reason there are many problems because PCOM will compensate if there is an occlusion of the p2 then we will have problems because there will be no compensation and then it comes by central and cortical branches let's take the cortical branches as the term implies these are the cortical supplies again we will not memorize these names I have written them just for your month it supplies the entire occipital lobe this is the dividing line this is the paritoxial sulcus which all of you know very well this is the paritoxial sulcus up to here was supplied by AC if you remember so this supplies the paritoxial branch, the calcarine branch and the temporal branch it supplies the entire occipital lobe it supplies the entire medial surface of the temporal lobe cortex, I am talking of the cortical branch just mind you but please follow me here if you do not supply the temporal pole it does not supply the hip of the temporal lobe the temporal pole because that is supplied by MC coming to the lateral surface it supplies the inferior temporal virus which was not supplied by MCA it is not shown in this picture it is shown in the previous picture so these are the cortical supplies of it also supplied by the hippocampus by the hippocampus artery so remember PCA supplies the visual area it supplies the memory area it supplies the hippocampus these are the cortical supplies of PCA coming to the central branches of PCA central branches of PCA are these branches can you see the PCA here these branches which are coming out these are the most true medial central perforating branches so how many central perforating branches have we seen till now anterior medial central perforating from the ACA anterior lateral central perforating which is from the MCA which produces the lenticulostriate arteries of cerebral hemorrhage these perforate again through the brain substance through another region of the brain which is called the posterior perforated substance posterior perforated substance is in the cerebrofenal lobe and they enter the brain at right angles they are also connecting branches that's why they are called perforating end arteries they give rise to several branches these central branches and some of them are important to us one, it's a linear art it supplies the posterior one-fifth of the corpus callus very important to remember two, it gives rise to the posterior thalamus perforating which you cannot see here and we have already seen this art in our chapter thalamus it supplies the posterior part of thalamus and it produces occlusion of this ischemic or hemorrhageic infarction of this produces can anybody tell me do we remember the thalamic pain syndrome is there in lucy syndrome it is produced by occlusion of this posterior thalamus perforating perforating should click a bell in your mind it is a perforating branch end artery it can get occluded ischemic infarction or hemorrhage infarction and it produces hemorrhageic infarction next you can see this branch it supplies coroidal branches posterior lateral coroidal and posterior medial coroidal posterior lateral coroidal branches they supply the coroidal ventricle posterior medial coroidal branches supply coroidal ventricle third this is again I mentioned this in the chapter ventricle coroidal ventricle is supplied by both anterior coroidal anterior coroidal as well as posterior coroidal posterior coroidal comes from PCA anterior coroidal from internal coroidal and the third ventricle is supplied by posterior coroidal only from the PCA so these are the important central branches of PCA and finally this is again summary slide you can see in this picture by this color coding the areas of supply of PCA both from the lateral surface of the brain as well as the major surface of the brain major surface of the brain major surface of the brain major surface of the brain lateral surface of the brain to form a good visual image of the coroidal supply and take a break and we will continue with the rest this slide