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So it's just going live, it's just loading. Good evening everyone. Uh Welcome to another session from er Central Clinical and MRC Sa Anatomy. Uh My name is CJ Sarata and I'm speaking for the foundation trainee Surgical Society, East Midlands. Er, today we're welcoming professor, hope a neurosurgeon who will be speaking to us about head anatomy. Er I'll pass on to the professor. Ok, good evening, everybody. And I start off by wishing you all the very best with the fourth coming exams in May. Um I'm a retired neurosurgeon from Queens Medical Center, Nottingham. I still go off to Kathmandu over the last 20 years and operate there or assist more than operating and I do a lot of teaching there as well um as regards to the college exams. Um as I said to um my colleague who's introduced me, I am not an anatomist at the college, but I've peeped over the shoulder of the anatomy of friends as I call them and seen what they have done in the part B exam. I've never been privy to the multiple choice question paper, but I've seen quite a lot of stations in the ACY and so on. So some of my er knowledge of things that come up are based upon that and I'm very free to answer any questions. So let's go on to the first slide. Um I start off very simply talking about the scalp. Um And we all remember the pneumonic sc A LP skin connective tissue, what I call the gia aponeurosis, by the way. So perhaps it should have a small g loose connective tissue and the periosteum. Is there any surgical relevance to this? Yes, there is one of the things that happens daily is cuts to the scalp, um, injuries to the scalp, some of which are quite minor and they come to the accident emergency department every day, particularly in the evening. And I've seen many scalp wounds badly treated. Um What I would say is that if the edge of the scalp wound is contused, crushed, um then it should be excised until you get to good bleeding tissue. Usually this is just AAA number 11, scalpel blade, take the edge off and then it should be bleeding free. Obviously, if there's any foreign material in there, it must be very carefully cleaned out. And the thing that is important is if it's a full thickness scalp wound, then it's not appropriate to close it without separately closing the gallia aponeurotica. But if it's a superficial wound, then by all means, just put in your sutures. And I prefer always not to use silk. I would prefer to use a, a monofilament. Uh If anyone wants to come back about the scalp, uh even now, do you want to ask any questions about that? Ok. No, I'm gonna go on pointing to the juror. We, we, we'll be talking about skull fractures later on. And the important thing always, and it's been known for thousands of years. It has the fracture of the bone penetrated. The juror is the juror involved. So if it's a, a, a compound depressed fracture, we now call it uh it's not, it's called what it's not called compound anymore. What's it called? I've forgotten the name. But if the a fracture has torn the juror, it's a much more serious and it has to be urgently elevated in a juro repair because of the risk of infection. Now, let's look at a lateral picture uh diagram of the skull. And what I think is important here is to draw this horizontal line, which is called after a man called Reid, apparently RE ID. And this is the Reed's baseline and that line is the baseline for the CT scanner. So all CT cuts, unless the technician asks for it lower down, but CTS cuts, cuts of the brain will start at the re baseline. We'll talk a little bit more of this type type of diagram in a moment. So remember Reid's baseline going through midpoint of the nose uh through the external auditory maus and coming to the external occipital protrusions. So that's more or less the baseline. Now, let's look at the sutures of the scalp and I've chosen a newborn scalp, not for any particular reason except it shows the anterior fontanelle. And we got the, we're sometimes asked in the exams about someone may point to various sutures and ask for the name. And we've got the metopic suture coming towards the anterior fontanelle which closes round about the eighth to ninth month. It should be certainly closed by a year and we have the posterior fontanel, which is not so important. Of course, the Fontanelle uh is important in pediatric neurosurgery because hydrocephalus er causes fontanel to be um uh tense as it were. You don't get the normal pulsation if you gently put your finger on the Fontanelle, um we then we have the Coronal suture here going back to the Fontanelle very useful in um neurosurgery in pediatrics because it's very simple to do an ultrasound by putting an ultrasound probe over the anterior fontanelle, getting a very reasonable image of the ventricles er in the coronal plane. Um So that's something to bear in mind. So the fact that the fontanel is still open is very useful in terms of uh a simple ultrasound examination for ventricular size as in hydrocephalus, we have the sagittal suture and we have the uh the lambdoid suture which is not seen very well on this diagram, what can go wrong? Well, again if I'm going to be neurosurgical. These sutures can, er, fail to, uh to anastomose, uh fail to uh join, er, particularly with hydrocephalus when the skull becomes enlarged. And then the opposite is there is a thing called synostosis, which I just want you to be uh aware of because it causes deformities of the head. And I don't want you to go into that because it's a, a pediatric neurosurgical craniosynostosis, premature fusion of the various er sutures. Let's go on to the next slide and here on the lateral we have again, the coronal suture. Um What else can we have the temporal bone, the parietal bone, the frontal bone, the orbit, we're gonna talk more about that. We're gonna talk about the nasal uh aspect as well and we're gonna talk about the mandible. Um And there's not very much else to, to actually point here the um the the temporal fossa, uh the uh the the temporal fossa here uh the orbit we're going to move, move on. We'll be talking about the mandible as well. Next slide, please. He said to himself. So here we have the lateral diagram of the skull. And what does it show us what it shows again, reads baseline. Um And it shows the position of a very important structure, the middle meningeal artery and the middle meningeal artery grooves the particularly the inside of the skull and the grooves on a lateral skull X ray. In my past experience have been mistaken for a skull fracture in the accident and emergency department actually doing a skull X ray for fracture is becoming a bit old hat. And if you feel that a person needs a a skull investigation is probably gonna nowadays going to be act scan. I'm still very fond of the lateral and frontal skull x rays. So we see the line of the middle meningeal artery. Remember the middle meningeal artery is a branch uh uh of the uh maxillary artery uh which again is the external carotid supply. So this is the one vessel inside the cranium, which is external carotid because the circle of Willis which we're coming to later is made of the internal carotid. And we have very important for me as a neurosurgeon. We mustn't forget that the uh the, the sinus, the, the big venous sinus, the transverse sinus and the internal jugular vein are very easily damaged. If you start to do a craniotomy too low, we're gonna talk about this circle as the pterion in a, a little while. So we'll go on to the next slide and here we have uh a rather similar lateral from the right hand side. Now, what I want to show here again is of neurosurgical importance. If we take this point here, I'm hovering over what's called the nasion at the top of the nasal bone. And then we come right away down to the external occipital protrudens, which is in Greek called the Inon. And we measure from the nasion to the inon, er, it with a tape measure and we come to the 50% level halfway between the nasion and the inon. And then if we come back about an inch or two centimeters and then draw a line down to the middle aspect of the, er, of the maxilla, maxillary bone. That is the line of the coronal, er, the central sulcus of the brain. So you can get a very good idea when you uh have got the anesthetized patient where the er central sulcus is with a precentral and postcentral gyrus. Once you've opened the head, any questions about that? Nothing as of yet? Ok. Fine. So remember one inch or two centimeters behind the midpoint nasion inon that has been asked in exams, by the way. Now let's go on a little bit more neuro wise to uh an angiogram. Again, I've seen this asked, I've seen an angiogram put up uh in the anatomy bay. Um and they've been asked, what is this artery? Here is the lateral uh carotid angiogram. So here's the internal carotid, here's the carotid siphon and it's a bit more on the lateral than it is on the anterior posterior to name the arteries. But these are basically the middle cerebral arteries. And here they are beautifully seen here. Remember, the middle cerebral arteries are supplying a, a large part of the motor cortex except for the anterior cerebral, which is supplying the frontal area. So we've got the midline uh anterior cerebral pad vessels here in the midline. Um and the median, the middle cerebral arteries branching out uh in uh in the um between the temporal lobe and the parietal lobe. The insular nearly forgot the word the insular. Now just it so happened that when I downloaded these images, there was AAA carotid angiogram that has nothing to do with the intracranial contents. But it's a common uh picture to see a carotid stenosis. And I as a neurosurgeon uh much to the chagrin of the vascular surgeons in Nottingham used to do a lot of carotid endarterectomy uh to uh in people who are having transient ischemic attacks, particularly of the carotid stenosis is more than 75%. And that was something we got out from uh trials many years ago, both in America and in Europe that if the narrowing is more than 75% the patient who's had a recoverable minor stroke or a tia best to put them on not only anti antiplatelet drugs but also urgently in the next few days, even do a carotid, do a carotid endarterectomy. Uh The carotid angiogram is done less and less. Now, in that case, because we get beautiful pictures from carotid ultrasonography, which obviously isn't invasive. So the ultrasound uh can actually replace virtually the carotid. So we've got the internal carotid external carotid, remember, the internal carotid has no branches in the neck. You've already had a a lecture from someone on the neck. So I won't go on that. Uh So here is the external and here we have the vertebral angiogram. So here are the two vertebral arteries. Often one is more dominant than the other. And the two vertebrals join uh to make the um basilar artery. And then we have the two posterior cerebral er I always think there is a beautiful tulip like shape and then the posterior cerebral er probably these are the posterior communicating that are coming backwards after the circle of Willis to make the circle in its entirety. Are we happy about that? Any questions? We've had one question which I'll read out er trauma to posterior fossa. Can it cause venous sinus E DH or is it more likely also arterial m ma more likely arterial um venous sinus hemorrhage? Thank God is, is very uncommon. Um I can talk about my experiences in this, particularly in the sagittal sinus, the big venous sinus and the sagittal plane. Uh but when you get bleeding there, it's often horrific but it's usually a a posterior branch of the er middle meningeal. OK. Is that happy? Right? Going on to the next slide and II talked to you earlier on about the pterion and this is sometimes asked can on a skull. Can you point out the area that's called the pterion? And it's the junction of these four bones? The frontal bone here, the parietal bone, the rather smaller sphenoid bone and the temporal bone and this junction is called the pterion important because a a large part of the middle meningeal artery is going in that direction and it's fractures in this region that are usually likely to cause extradural hematoma. Um We can talk more about extradural er in chat if you want. So here is the Teron and a different er diagram. Just remember that word Terry on. Um OK, let's go back to the scholars again. Now I'm showing this picture because we want to consider some of the foramina. And again, I've seen the sometimes ask the candidates been handed a skull picture or a a real skull and been asked to point out the supraorbital foramen, the infraorbital foramen and the mental foramen, the supraorbital nerve comes out through this over here and the intraorbital nerve comes out here with fissure, which we're gonna talk about in a minute. And if you get fractures of the superior rim of the orbit, then the patient has an area of anesthesia because of the er involvement of that nerve. So that's sometimes uh in itself both medical, legally important in terms of the poor victim, claiming persistent anesthesia in this region. Of course, it's a branch of the a ophthalmic division of the trigeminal. Whereas the infraorbital is a branch of the maxillary trigeminal. We're going to discuss that uh in more detail, Zygomatic arch, nasal septum, the, with the mandible, we're gonna talk about the zygomatic bone, uh the optic foramina inside the orbit and we're gonna discuss the er super superior orbital fissure and the structures that go through it in a minute. Let's look at the skull from the inferior aspect. And so these foramina er, are quite frequently asked, do you know, can you point to the framing o can you point to the uh the stylomastoid foramen? Can you point to the foramen spinosum, the carotid canal, the jugular foramen? Um And sometimes even you ask what goes through there. One, just a little joke, one candidate many years ago said the esophagus. Uh I'm sure that's OK. Right. Let's look at the. So now we're gonna look at fossa. So we have the anterior fossa with the um the superior great sorry, the greater wing of sphenoid has its posterior limit. Um the cribriform plate of the ethmoid very thin and the it this is through the cribriform plate. It's called that because of all the little holes are the olfactory nerve endings and this thin this is the thinnest area of the skull and in head injury, this is a common area for fracture. If the re form plate is fractured and if the JRA is torn, then as you'll hear in a moment, you might get cerebrospinal fluid leakage, then we have the middle fossa in which the temporal er er the temp the base of the temporal lobe of the brain er is situated and then we have the posterior fossa which is mainly occupied by the cerebellum um fen rotundum there for um the er branch of the trigeminal Framan ovale foramen spinosum, the little one and the fram and lacerum for the carotid internal auditory mats actually, sometimes that is a little bit more difficult to see on this view cos it's you need to tip the skull and then the jugular foramen for the jugular vein. Anything about that? Folks? Any question just had a request if we can go to full screen. So just at the bottom, professor, if you bring the cursor down, um if you see there's a, you see there's a zoom bar on the bottom of your screen where it says on the pathway. If you just go on the left of that, do you want me to move it small or big? Bigger if that's all right? Oh He's too big, too big. Um If you just go to the left of that zoom bar there, there's a uh there's a, do you see there's a button to the left of the Zumbar if you just bring just your cursor bit left of that, the next like that one. What is it? Yeah, I think everyone's happy with that. Now, if we just continue, um I don't think this is a very good picture actually when I reviewed it, but this is a pituitary fossa and you can see the foramen lacerum for the car or carotid canal. So, in pituitary surgery, we have to be very careful because we're working here, as you'll see in a, a later diagram. And it's quite easy to damage the carotid artery and to my chagrin, I did do that once. Fortunately, I managed to sort out the problem, but it's a terrible thing to actually go too far lateral in pituitary surgery, going through the sphenoid, we'll talk about this. So this is the hypophysis of cerebri in here, the pituitary fossa sometimes called the sella turcica with the anterior clinoid. And we don't see the posterior clinoid in the skull, anterior clinoid is that posterior clinoid and there's a strip of dura that goes between that and of course, there's a ring of dura that allows the pituitary gland to descend into the hypo into the pituitary fossa. Then we must talk a bit about the attachment of the Jura. And this is the falx cerebri dividing the two cerebral hemispheres in the anterior posterior er zone as they view the falx divides to have the the sagittal sinus. So if we were to put a blue line, the sagittal sinus would be going all the way along here and then the the fox comes down and becomes horizontal as the tentorium for the cerebellum. With it not seen on this diagram, a tentorial notch for the brain stem to go in either side of the notches of the two cerebellar hemispheres. So this the tent the 10, as we nickname it divides er, the cerebellum in here from the brain proper. So the occipital pole, the occipital lobe of the brain will be here and the poster, the er, the cerebellum will be in there and there is even a smaller falx, cerebri, the divide cerebelli that divides the two cerebellar hemispheres. Let's go back to this idea of SC A LP and the fact that we might get a, a fracture as so. So we've got a scalp laceration. This is a common, particularly on a Saturday night, particularly in Nottingham. Uh I've seen 100s of these and we get a scalp laceration, er, caused by a blow often as salt and then the skull is fractured and is the juror torn or not? Obviously on the CT scan, you can see that the bone is depressed and you may see air underneath the JRA on the CT scan that shows that the juror has been torn. So all I still use the term compound. Er, it, the modern term is open, depressed skull fractures. The one ancient surgical question is, is the jura intact. Now, of course, if the juror is torn and if there is an area of dead brain, then within 12 hours, one is likely to get uh either meningitis or a localized cerebral abscess and this would be considered completely incompetent surgery. So, is the juror intact a very important aspect of dural anatomy. Any questions on that? So, elevating an open depressed fracture is almost an emergency within say six or eight hours, it has to be done and we may have to do AJ repair. We sometimes use a bit of fasciata from the lateral aspect of the thigh uh as a dural substitute if the juror is confused. And of course, we wash all of this out and put the patient on antibiotics and T talks as well. Any questions, right? We talked about the anterior fossa. This is what I call the raccoon or panda sign. And this has been asked about in uh the MRC S just, I would like to be able to question the audience. What does it mean? Can I pause and ask what does it mean when you get bilateral black eyes like that after a head injury? So I just wanted to check. Professor, have you moved ahead the slide? We're still seeing the diagram of the uh Foramen Foramina. Well, I've moved on. So what's happened? Uh If you just go to the left hand side and click the slide you want to go to. So I'm, I'm, I'm pressing next and next is the Juro Anatomy. OK. Can you see the left hand menu that shows the slides? No, I've just got, I've got a full screen. OK. Um What's happened? Not quite sure. Um If you just hit escape and we'll repent. Oh, there we go. OK. So OK. So I was up to, to, to do that one. OK. What do I do now? There we go. Uh I think just at the bottom, right? If you zoom out just as we zoomed in earlier, if we zoom out a little bit, so we get the full screen. That good. That was, that took my breath away. So I shall I go again talking about the jury anatomy. Um the tent, the falx cerebri, the tent and the fact that the uh tentorium is the superior surface for this, the posterior fossa and the cerebra in here. And the falx is dividing the two cerebral hemispheres. And the sagittal sinus is where I'm now showing you with the cortex. The the the cursor are we happy? I think. So your eyes, your question with the this pander eyes. We've had a number of answers saying basal skull fracture. Yeah, I would like to add not quite just basal skull fracture, anterior fossa fracture. So when you get those raccoon panda sign, it's an anterior fossa in in brackets a basal skull fracture of the anterior fossa. Now, why is that important next slide because of that? So patients with an anterior fossa fracture and this is often missed by the way, um particularly in a non neurosurgical hospital with an A&E department. Um you could understand why nursing staff and young doctors would see a patient with bilateral black eyes after a head injury, who's alert and orientated, wouldn't think very much about it. And the important thing is, is the patient experiencing a drip of fluid down the nose. I've had half a dozen patients who months, no weeks later after discharge came to my Derby Clinic and say, is it right that I'm dripping this fluid down my nose, horror, horror, horror, because of the risk of meningitis in in fact, that didn't happen. So the anterior fossa fracture, particularly if it tears the jura in the region of the Revi form is likely to cause uh cerebrospinal fluid leakage and anos mere by the way, which may be permanent. And again, that has medical legal er aspects of claiming um and this is the typical rather severe aspect of a an anterior fossa fracture where the patient has now got a considerable amount of air inside the head um which on rare occasions can increase in volume and act as a space occupying lesion, the so called air cephal. I've only seen that on a couple of occasions, but that is air in the um sagittal plane of the CT scan. And it's usually uh quite modest. Now, we're still on the aspect of the, of the, of the fossa and here we have a different picture. So this, I think it's probably a lady but I'm not sure has got a bruise behind her ear in the region of the mastoid chat. What is that a common question in the MRC S by the way this is a fracture of the middle fossa. Usually the P is temporal bone. But what is it called? And what's his significance apart from indicating the fracture, does anyone know multiple? It is a battle sign, temporal bone fracture, correct? Yeah. Usually the picture is temporal bone well done. And the significance of it is that that patient may develop cerebrospinal fluid from the ear which is called CSF artery. And the other thing is it may have disturbed the um the ossicles of the ear and the patient may have a conductive deafness. And on uh on occasion, the pictures fracture, remember that the facial nerve goes through, it has led to a a bell style, lower motor neurone palsy. So those are all things that can happen as a direct result of battle sign, check the hearing, check, possibly balance cos it may disturb the vestibular apparatus as well. Uh and check the facial nerve. And is there any leakage? Um CSF O ear usually stops CSF rhinorrhea, rarely does so. So we rarely have to operate on CSF coming out of the ear. It usually stops spontaneously right back to the inner aspect of the skull. We talk about the middle meningeal and these are the branches of the middle meningeal which groove, they actually groove the inner aspect of the skull and can be mistaken by the way for skull fractures. Skull fractures are usually linear. Whereas if there is a curve, it's the middle meningeal. But I on a lot of occasions, people, junior doctors said, is that a fracture? I said no, it's the line of the middle meningeal artery. Ok. And here is an extra classic ct scan of an extradural hematoma. Um deviating away from anatomy in my examiner ship as a uh physiology. This slide has been shown in the osk. And the next question was why has the patient lost consciousness? Why has the patient's BP elevated and the pulse lower described cushing reflex? And why eventually might the pupil dilate describe the effect of the temporal lobe on the third nerve and the free edge of the 10. I know I'm deviating from anatomy but you can't really in exam deviate. Uh you can't separate anatomy from physiology. So just remember the extradural hematoma is a common MRC S question particularly in the um physiology. I in the intensive care aspect, any aspects of that, would you like to talk about that? We've just had one question. Uh Can we please explain the difference between longitudinal and transverse fracture in temporal petrous bone? Please? I want you to repeat that question. Can we please explain the difference between longitudinal and transverse fracture in temporal petrous bone? Please answer, I can't, I don't, don't understand the need for the question. Can we leave that to the end? I'm sure ignorance perhaps. But there's a, there's probably a reason for that question and I'd like to come back to it. Is that um I know that's ducking it. Can we come back to that at the end? No. Uh call me how we, how we, how can we compare the extra D with this biconvex lens appearance on the CT scan with the acute subdural course. Here it is the acute subdural again, by the way, both of those show shift of the brain and this is the typical subdural. This is a a comatose patient shortly after a severe head injury where the veins have been torn. Uh the cortical veins have been torn, whereas the extradural is caused by uh the middle meningeal. This is usually a patient who's been comatosed from the moment high speed road traffic accident and they're going downhill just as the middle men in jail will because of rising intracranial pressure. So it, it makes you suspect that the cortex is damaged and the outcome from acute subdural is nothing like as good as the successful surgery for extradural. There will be almost certainly not always brain damage with epilepsy, uh hemiparesis dysphasia months after the er evacuation of the acute subdural. Now, the other thing is that was a biconvex lens. You agree this is a concave in a er lens, convex versus concave. Now, so that's acute trauma in, in head injury. Here, we have a very common elderly problem. People of my age who fall down stairs, particularly if they've um taking antiplatelet drugs like aspirin or whatever. And this is because of the aging population, a very common uh A&E presentation of the confused elderly patient. And in fact, the trauma may have been forgotten about and this is the chronic subdural hematoma. So, the elderly patient with neurological signs that where it's come on over days, particularly if their history is known, is possibly suffering from chronic subdural, excuse me. And the reason that's so important to diagnose, it's very easily treated by one or two bur holes draining the chronic subdural and the patient uh regains their normal self. Uh The, so this is the fact that the brain as we age shrinks and the veins are straddled across to the dura er from the cortical surface. And a a minor trauma can tear the vein, the vein er makes a little pocket as it were, it becomes walled off. And we believe that the membrane of the of the venous hematoma gradually brings in more fluid and as the weeks and months go by or the CSF sorry, the uh the hematoma becomes liquefied and expands chronic subdural hematoma. A common cause in the elderly of confusion with possibly no history of trauma or the trauma has been forgotten about weeks before. Um Let's go on to the mandible. Um What can we see the lateral aspect of the mandible, the inner aspect of the mandible and we must be able to know the coronoid process, the head of the mandible. Uh Here articulating within the temporal mandibular joint, the ramus of the mandible, the angles of the mandible. And I've already mentioned the mental foramen through which the nerve passes and then the inner aspect we see the same. I'm going to talk about alveolar block shortly. Um I've not heard any questions about the fossa for the submandibular gland or the sublingual er in the old Mr CSI think that's the sort of thing cos the anatomy was they could ask you anything but bear that in mind. Let's look at fractures of the face. This is something I think you should have heard about after a man, presumably a French le fort classification of facial fractures. This this is the patient who's had anterior fossa, uh sorry, anterior fal injury, particularly from a motorbike coming off at speed, um particularly if they don't wear, wear proper crush helmets. And we have type one, which is only involving the uh the maxilla. Type two is going uh up into the nasal region and type three is involving the inner aspect of the orbit and the floor of the orbit. What is the importance of all of these fractures? They tend to cause acute airway obstruction. And of course, in terms of atl s uh treatment of the er head injured, patient airway is very important. So, le four fractures are the province of the accident emergency doctor along with an emergency maxillofacial surgeon. Um they are fractures that will probably lead to a tracheostomy being done and wiring uh of the er fracture with the help of CT scan reconstruction from the maxillofacial surgeon. Let's go back to the mandible. This is a very important uh nerve blocker, very useful for you. And I if we've got bad teeth and require a filling or uh God forbid a tooth coming out. Um So the dental surgeon passes a needle deep to the last molar on the inner aspect of the ramus of the mandible. And he's getting the mental branch of the inferior alveolar nerve, also affecting the tongue to a certain extent. So this is a, a nerve block that's done every day by your dentist uh using uh lignocaine or I think that's the commonest anesthetic rather than procaine. And in two hours, the anesthesia passes off any questions about that. So we had a previously uh asking you to speak about the Monro Tele doctrine. Now, I want to come to that at the end cos that is we're now talking about physiology of raising the cranial pressure. Can you mark that down as a chat session for the end? It's important question. OK. Have done. Um Now let's go to the orbit. I've heard this asked as a question. Can you name the seven bones of the orbit, uh the nasal bone, the frontal bone, er the er sphenoid bone, uh the zygomatic bone and then this little uh bit er the palatine bone in there and the amo bone. Those are the seven bones of the orbit. Uh Did I get that right? 12, three, so 567. Yeah. OK. Any questions about that superior orbital fissure optic canal for the optic nerve, inferior orbital fissure? We're gonna talk a little bit about this in a second. Here is a diagram of the superior orbital fissure. I don't know why this is so often asked. Um There is a rather rude mnemonic that I'm not prepared to broadcast. Uh but it's LFT SN eight. No, SN I. And it's lacrimal frontal trochlear, the superior branch of the oculomotor nerve, the nasociliary nerve, the abducence of the sixth cranial nerve and the inferior branch of the oculomotor. And then you can add it in er externally the inferior branch of the ophthalmic and severe branch of the ophthalmic vein. So do I do suggest that you actually write down the contents of the superior orbital fissure? Why this is asked so often? I do not know, but it is a common anatomy question. Any, any comments, I'm not prepared to give you the dirty mnemonic. No questions at this time. Thank God. No, we talked about the anterior aspect of the skull and the some of us have got bigger or smaller frontal air sinuses. And if I as a neurosurgeon stupidly uh take the craniotomy down into the frontal sinus, then I'm worried because the, the front, the sinuses are occupied by commensal bacteria commensal. And if you actually get sinusitis, and it's possible that this may go up and develop a frontal lobe abscess of the brain. So, frontal sinusitis leads to an abscess on a cane mastoiditis would lead to a cerebellar abscess. Uh And those are the common abscesses of the brain from infection. If it turns the juro, we've talked about cerebrospinal fluid, uh particularly in the cribriform plate of the amo sometimes you get a leak down the opposite side. Um I've mentioned about the flap actually when I actually accidentally have entered the frontal air sinus, which is naughty because you should look carefully at the anterior er skull X ray or the CT scan. I've not been too worried because I wash it out with hydrogen peroxide, put the patient on antibiotics and it's never been a problem, but I still think I shouldn't have done that. Now, the inferior aspect of the orbit can be fractured. Um And by usually injuries that involve direct anterior posterior force to the globe of the eye and then the eyeball muscles collapse down through the fracture. And this is nicknamed a blowout fracture of the orbit. And it's very important, particularly from the point of view of maxillofacial surgery and the ophthalmologists who tend to see these patients in the department, this er poor person is being asked to look up and manage to do that, but this eye is restricted because the inferior er rectal recti muscles of the orbit are being uh retracted, not retracted, being uh pulled down, being hindered from allowing elevation of the eye. So that's a classic sign of a blowout fracture. Recently, there was an article in the no an article, it was uh end Games in the British Medical Journal, a quiz why a patient who was being asked to look up suddenly fainted. And the reason apparently is that when you look up with this type of blowout fracture, you can get a, an intense vagal ophthalmic vagal trigeminal reflex that leads to bradycardia and uh uh and even syncope. So sometimes pain on looking up, followed by a slurring of the pulse. I think that's a bit. Er, but I don't know whether anyone's ever come across that. Let's go to something that's very important for neurosurgeons who operate on the pituitary gland. And we look carefully at the CT scan. I know this is just a diagram to make sure that the nasal sep the, the, the septum of the sphenoid air air sinus is midline. Sometimes it's more to one side than the other. And it's very important to take that in consider co on once a midline uh up the, we lift, we make the incision underneath the lip or some surgeons go directly up the nose. Um and we get, we tap our way into the sphenoid sinus and then into the er, into the cribriform, into the er sella Turcica. Now, what we have to be very careful of is when we're actually removing the bone, to get into the pituitary, to remove a, a pituitary tumor transsphenoidally is the position of the carotid artery. So the cavernous sinus region here, this is the cavernous sinus, has the carotid artery in it and in the lateral wall of the cavernous sinus, as you must know, very important anatomy. Question. 34, V one V two and six, six is sometimes in the lateral wall or sometimes in the cavernous sinus. What I haven't shown in here is the possibility of veins being in the caverna sinus. Well, the cavernous sinus is of the big vein itself. Stupid question. And we can get carotid cavernous fistula where a small hole in the carotid from trauma communicates with the cavernous sinus and then the patient and develops a bruit in the orbit orbital region and exophthalmos develops within an hour or two carotid cavernous fistula treated nowadays by interventional radiologists who can seal the hole in the carotid artery. Any questions about caroticocavernous fistula, not common, but sometimes actually associated with quite minor trauma to the head injured patient who then then may be discharged and come back the next day with a very red eye. And doctor I've got this noise in my head and my eye, I can't move my eye because the, the the eye is becoming engorged, the conjunctiva engorged and it's an emergency to be treated. Um, a very anterior ct scan with the midline nasal septum and the turbinates. Uh and the mag er and the sinuses, the maxillary sinus which becomes cloudy and gray in sinusitis, uh which I think I'm suffering from at the moment, by the way, so that my maxillary er air sinuses probably need a CT scan. So I've said this in patients with the pituitary tumors, the gland may be approached endoscopically or not necessarily endoscopically, but actually by microscope, I've never used an endoscope. My younger colleagues are doing that now by the transsphenoidal route. Obviously, if the pituitary tumor is very big, then we do a a AAA craniotomy because of the pressure that the big tumor will cause on the optic chiasm to say nothing of the endocrine aspects. By the way. Um Now I'm coming to the parotid gland. I had a parotid tumor excised when I was a senior registrar. We don't use term senior registrar, but I was in my thirties waiting for my consultant uh opportunity and I had a tumor called a mixed parotid tumor. And so my wonderful um surgeon in Bristol removed my mixed parotid tumor and managed to save my facial nerve and the facial nerve is traveling traversing from the stylomastoid foramen where it comes out uh through the carotid between the superficial and deep parts of the parotid. So parotid surgery, uh occasionally parotid trauma. I saw a lady in Kathmandu who was uh using a sickle to cut her rice the sickle came up and she got a cut right across her parotid. She developed a protid fistula and she also damaged her er facial nerve. So remember the important aspect of the facial nerve and the parotid gland, I, I've got a next diagram of the facial nerve. So it's come out through the stylomastoid foramen, it's passed through the parotid shortly after exit and it develop, develops into the frontal um zygomatic and the mandibular branches. There are many of these branches. I don't think it's an anatomical aspect tonight, but I mean testing the facial nerve as an osk is quite a common uh MRC S er OSK station. Remember the facial nerve is supplying the um uh the ability to close, tightly, close your eyes um to uh lift up your eyebrows, uh the frontalis muscle uh to um blow out your cheeks, buccinator and make a big er smile, which is risor. So we must know how to test the facial nerve, lower motor neurone complete paralysis of all those muscles to a greater or lesser extent we so called Bell's palsy, upper motor neurone facial weakness eventually spares the upper third of the face because the bicortical representation in upper motor neuro fal. So someone that had a stroke, eventually their forehead will be spared, but the lower two thirds will be weak. Ok. Let's just talk a little bit about the uh circulation affecting the uh the circle, the circle of Willis. I'm going to do this. I'll come back to that slide. Here is the circle of Willis. Ok. The internal carotid, the anterior communicator, the anterior cerebral arteries coming off going to supply the frontal polar and coming over the pole of the brain. The um internal carotid um er quickly making a branch for the middle cerebral posterior communicator to come back to the vertebra basilar system joining the basilar er the posterior cerebral and then the branches of the basilar. I'm not talking about today, but you can look at those of superior cerebellar aca anterior inferior cerebellar artery, pi, posterior inferior cerebellar artery often coming off the vertebral, the vertebral basilar, sometimes badly called the posterior circulation and this is sometimes called the anterior circulation. So when we look at the brain here, this is um uh very much in the right is the area of the middle cerebral. And of course, this is mainly motor cortex. This is the anterior cerebral. If you get a stroke of the anterior cerebral, the leg area uh of the homunculus will be affected and you'll get weakness only of the leg. Whereas this area will possibly affect the leg but mainly arm uh and uh lower limb uh um arm and upper limb, sorry arm as upper limb and speech may be affected on the dominant hemisphere. So, anterior cerebral, middle cerebral and then we have the posterior er cerebral er which of course, if you get stroke affecting the posterior cerebral, you may get a um a a visual field defect, not a very common stroke. By the way, posterior cerebral. Um This can you describe the suboccipital triangle of the neck in the old anatomy virus. This was a common question when we had a cadaver but now they've got wonderful ct scan replicas of cadaveric material. And it's the, the triangle in the, the, the suboccipital triangle is made of the rectus capta, posterior major. The in the two oblique muscles, the superior and inferior oblique capitis muscle. What is the significance of the suboccipital triangle? The answer is in the triangle lies the vertebral artery. The t the tentorial membrane is underneath that. Um And so this is a very important aspect for head and neck surgery from the posterior aspect. Don't go out too far and damage the vertebral artery. These, this is the junction of the spinus o process of the second cervical vertebrae. I think we're coming to almost the last slide. Er the distribution of the uh sensory aspect of the trigeminal nerve, ophthalmic and green maxillary division in blue and the mandibular division uh of the sensory uh sometimes called V one V two V three of the trigeminal sensory. Remember the trigeminal, the fifth cranial nerve is both sensory and motor. Look how the back of the scalp is actually supplied not by trigger but by a nerve called the greater occipital coming up, er which is mainly c two, the second cervical er se er er dermatome C two. This is uh from the C three and C four region dermatome wise, a little area of the angle of the mandible is not supplied by trigeminal. This is a, the neuro neurologists are quite fond of pointing that out because if you get a a hysterical facial numbness and it involves the angle of the mandible, it is not organic, it's functional. I've never had to to to do that with a patient. Now, coming to the motor aspect of the trigeminal, remember we've got to test the temporalis, muscle clench your teeth and put your fingers on the temporalis and feel it uh tense up, open your jaw against resistance, er which is er pterygoid. And if a pterygoid is weak, the jaw deviates to the to the weak side, clench your teeth together and put your fingers on the masseter. So the three muscles are temporalis, massa and the pterygoid. When you grind your teeth like a cow chewing, the curd that lateral movement is through the pterygoid. So remember those muscles and that is it? OK. Let's open the chat session. Are you still there? Yes. So we haven't got any further questions in the chat. So the ones that we have are the Monro Kry doctrine. If you let's go, let's talk about the Monro the the I can't show a slide about it, but there's plenty of it on the internet. Um When you get rising intracranial pressure as in say a, a an extradural or subdural hematoma. The the Mro hypothesis said there are volumes of blood inside the head, venous and arterial. Normally speaking, there's a volume of the brain and there's a volume of the cerebrospinal fluid in the ventricles and in the subarachnoid space. And the Munro Doctrine says that any of those volumes increasing in size, brain brain swelling or let's take the extradural as being brain uh or a chronic acute subdural or CSF hydrocephalus. Um and so on causes raising the cranial pressure. So raising the cranial pressure, the ra the mon colleague, Kelly Di A hypothesis says it's due to an increase in one of those volumes when you get a an increase in intracranial pressure because of that, you will get certain signs, particularly uh red reduction in the level of of consciousness. Um You will get the cushing reflex which is bradycardia and a rising BP, happy hypertension, a slowing of the pulse and a uh increase in BP because of the in ip intracranial pressure, indirectly affecting the medulla oblongata, possibly the vagal er nuclei are involved in that in terms of slowing. And the cardio motor center in the medulla causes the rise intracranial pressure and eventually with the uh ICP going up. By virtue of the Munro hypothesis, the pupil will start to dilate on the side particularly in a hematoma as a a late late sign of inial pressure. If it comes on very slowly, the, the ICP as in hydrocephalus or in the brain tumor, then the, the rising pressure will be manifest by papilledema by an ophthalmoscope showing the, the fundus being swollen, but that's a late sign. So the, again, the Munro Kelly hypothesis states there are three volumes inside the cranium. Any volume increasing will cause a rise in intracranial pressure. And then I'll describe what happens as a result of that. Are we happy? Any, any comment? So, er nothing further there, we've er they've just said thank you. Er, we have, when is surgical intervention indicated in CSF leak and when can they resolve on their own? Ok, good questions. Um Cerebrospinal fluid, rhinorrhea, dripping down the nose is usually nowadays looked upon by the neurosurgeon with his helpful colleague in ear, nose and throat and endoscopically by putting the telescope up the nose, the ear, nose and throat surgeons can seal it very cleverly. So we in the old days, we used to have to open the head, take a graft from the fascia lata and put it down on a group form, reach a communist area for the fracture. So with, with, with modest fracture, in terms of the size of the fracture and CSF leak down the nose, it's usually our colleagues in ear, nose and throat. Obviously, if it's a big tear I mentioned, for instance, the patient with a so called le four or a basal uh in the base of the skull, then we have to open the cranium and seal it, seal it a dural substitute fo from the ear rarely requires intervention. But in both cases, I think it's wise to give the patient antibiotics whilst the repair is being considered. Ok. Yeah. Any questions. There's the previous question uh that we could come back to er about explaining the difference between longitudinal and transverse fracture in temporal petrous bone. Um If you are able to put any um further clarification of your question in the chat, if you'd like, we'll just see how I feel extremely ignorant as to the purpose of the question. I I'm I'm just, I'm mystified just between a, a longitudinal and a. Uh So it's please explain the difference between longitudinal and transverse fracture in temporal petrous bone. I can't answer that question. I feel I II don't see the significance of it and I'm sure there is a significance, but I'm just being stupid. We've just heard. I think it must be in relation to the question about er CF leak er comment and say the test is B2 transferrin. Most of the fractures of the prus, temporal bone that I've seen have been transverse. I've not seen a longitudinal one. It's usually right across the the ridge and it may involve the facial nerve. By the way, the pits, temporal bone, it's called prus because it's very hard petra as in rock as in Saint Peter the saint. So it's quite a, quite a difficult fracture to occur, but it doesn't occur. A and again, a PRS temporal fracture would be commensurate with battle sign with bruising of the mast around the mastoid. OK. I can't see any further questions. I'll give people one more minute if they have any questions they'd like to ask or if there's anything they'd further like to clarify, put in the chat. I, I'll tell you what would be useful for me. Um I haven't covered some of the aspects that pos possibly that they were hoping for. I don't know, and a little bit of feedback would be very helpful, gentle feed or not even, not even gentle aggressive feedback. What, what would they, I mean, I didn't do much neuroanatomy because I II suspect that detailed neuroanatomy is not what was required tonight, but I hope I'm right. I'm right in that regard. So I have some comments. Uh It was very succinct and clear. Thank you. Oh, good. So as I further mentioned to the people attending today on finishing uh the session today, if you are able to fill out our feedback forms as well. Well, uh uh we'll get your certificates after doing so and we can pass those feedback forms onto professor. Hope so. He'll be able to see your comments there also. Um Great surgical relevance. Thank you. Is it not current? Good, good. I mean, the feedback is more useful if in fact, there are some negative aspects, you know, I wish you had talked about XY or Z that, I mean, II II hasten to add, I'm not an anatomist, you know. Um and I I've been doing this uh just on past experience of the exam. Um just whilst I'm wetting if, if one will, if sperm said which cranial nerves are commonly asked about, excuse my bad English, I would say the optic nerve, uh particularly as regards visual field defects, the oculomotor nerve, the trochlea and the uh trigeminal and facial. They're the commonest cranial nerves to know about 34 and 65 and two and seven. That's my tip. We've just had one further question is the superior orbital fissure, an important landmark in neurosurgery. Yes. Um particularly if one is doing surgery in conjunction with a maxillofacial surgeon, uh for whatever reason, because nowadays, we work as teams and if a patient is requiring is I mentioned the, the le four fracture. But we also involve maxillofacial surgeons in actually taking the roof of the orbit off to give us a very horizontal access to some tumors. I don't think the superior orbital fissure is so important for neurosurgeons except in doing craniofacial neurosurgery. With the team aspect, didn't I did not mention the, the the superior sagittal sinus and the fact that the, the ano vili invaginate into the superior sagittal sinus and are very important in terms of CSF transfer. I mean we make CSF in the ventricles from the choroid plexus. But the CSF is mainly absorbed through the Arachnoid vili that project into the superior sagittal sinus. We in the last 10 or 15 years, we are more and more aware of the possibility like a deep venous thrombosis in the leg. We can get the venous sinuses of the brain obstructed by thrombotic events um particularly in the superior sagittal sinus. And this causes raised intracranial pressure because the cerebral veins can't drain properly. So remember the arachnoid vili sometimes called the pian granulations that invaginate the arachnoid into the superior CIN. And this is our mechanism for CSF absorption back into the big vein. We make about 500 to 600 mils of CSF every day. A further request um is if we can talk a little bit about CSF leaks, right? Ok. Um I would divide those into iatrogenic caused by the surgeon and trauma and occasionally but rarely spontaneous. Let's take trauma, basal skull fractures, as I've mentioned, can cause cerebrospinal fluid from the nose or the ear. I think I'm reasonably right in saying the cerebrospinal fluid coming down, the nose is not likely to stop by itself. The risk is meningitis and air entering the the skull even uh e entering the intracranial cavity causing gradually rising intracranial pressure, but particularly infection. So CSF leak down the nose requires pretty urgent investigation. CSF otter from the ear again to be taken seriously, but usually it stops. But remember the possibility also of balance and hearing problems and very rarely even the facial nerve being damaged by the fracture, iatrogenic cerebrospinal fluid caused by neurosurgery is unfortunately quite common. And in the posterior fossa when we do uh acoustic neuroma removal, um the, the fact that we've got to open the jura in the posterior fossa, it's sometimes quite difficult to actually get the JRA reapproximated by suturing it. And if I said that my friends who do a lot of acoustic neuroma surgery, get something like a 5% CSF leak through the wound, uh through the posterior fossa wound, then have to go back to theater. That's, that's, that's the way it is. Um What else can I say, spontaneous cerebrospinal fluid can lead to low pressure, intracranial uh headaches. And I thought that was pretty uncommon until a professor, a friend of mine in Kathmandu, a lady realized that she was getting increasing headaches when she stood up. This was only the last couple of months and it turned out that she had a, an osteophyte, a little bony spur in her thoracic vertebrae that had actually torn through her dura in the thoracic region and she was getting a CSF leak there. Uh She was given a lumbar puncture and blood was put in through the lumbar puncture to seal it. It's what we call a lumbar tap sealing procedure or a blood tap. So occasionally we can get low pressure headaches. And of course, after a lumbar puncture, when we, we, we've done uh an investigation of the CSF for whatever reason, as in say meningitis or measuring the pressure, low pressure headache. After a lumbar puncture is a common problem. That's why we like to keep the patient in bed for a few hours hoping that the tiny pinhole will seal itself. Is that ok? One further question, uh we diagnose it with Halo sign and MRI or is it just obvious visually? I want you to say that again. Is it what we diagnose it with Halo sign and MRI or is it just obvious visually what the CSF leak? Yes, it's obviously visually and then it's confirmed. But usually first of all, by act scan, even a skull X ray will show air. No, it's very easy to see. The patient is dripping clear fluid down the nose. And then you would go on to, to look at the CT scan and see is there any air there? And you might ask for CT reconstructions cos you can do a CT scan, a AP and lateral and the computer can do AAA very clever 3D reconstruction. If there's no further questions, I think we'll call in even we just had a, had a th another. Thank you. Uh Thank you very much, Professor Ho for coming to speak to us. Your doctor has been excellent. OK. Thank you. Um And say that I'm always available if we want to do another session with more neuro. Ok. Thank you very much Oliver.