 Hospital Skolkata. And with this, I start my ortho series, this afternoon's ortho series of our ever favorite MSK, conventional masterclass. And there are back-to-back lectures. And this is the first lecture. And unfortunately, it is coinciding with the lunchtime. And I'm very sorry for that. Please bear with me for the next few minutes. And to make it a little interesting, I have tried to make it a little colorful. This background of my first slide suggests so, because bone radiograph, after all, is all about various shades of gray and dull colors. Now, let's see if you feel colorful at the end of this lecture. Now, to begin with, I have to say that this lecture is not based on any particular entity, nor is it based on any particular pathology. It is an approach-based lecture. So I am not going to details about any entities. It is how you should approach a bone radiograph, whether it is, this lecture is particular helpful for residents to answer any bone radiograph when it is given in front of them in the exam. And not only that, also when they pass out in their regular practice, how to read a bone radiograph. For that matter, residents remember that whether it is a bone radiograph, CT, MRI, if you have an algorithm in mind, if you have a certain format, and if you go step by step, then first of all, you don't miss any findings. And number two, your report is way different from others who just haphazardly put into words whatever they see. Now, what are the questions that come into mind when a radiograph is kept in front of you, whether in due to your practice or whether when you're giving an exam? If you answer these few questions that I will be discussing throughout the lecture and at the end, write it, you will find your report very, very clinically pertinent, answering to the questions of your clinician, narrowing the DD rather than making him confused. And last but not the least, the clinician will have a habit of going through your report rather than just saying that I don't even need the report, just give me the film, I'll review it. No, your report will be such that every time the clinician who has referred will go through it and yes, come to a conclusion. So what are the questions that should come in mind that you should keep it before writing the report? Number one, what is the density pattern? My lecture is based on these following questions. What is the density pattern in a bone radiograph? Mark the portions in red, that is what has to be imprinted in your mind at the end of your lecture. So first I'll discuss what is the density pattern of structures I see in a bone radiograph? Next, what parts of a bone are we studying in a radiograph? Number three, whose bone am I seeing? Is it a pediatric patient, an adult or a geriatric? Which bone am I seeing? Are these bones a part of a small joint or a large joint? If so, what are the number of bones that we have to carefully see? Question number five and the most important, why have I been asked to study this radiograph? What is the clinical suspicion? And lastly, just don't stop after seeing the bones. See the nook and corner of the radiograph to see whether I've overlooked anything outside the bones. So let's see one by one each of these questions. Number one, what is the density pattern that we see instructed of a bone radiograph? Now, Andrew felt sorry for whatever this mnemonic is over here is just denoting that on one end of the spectrum is air and one end of the spectrum is metal. Now, x-ray, first of all, one more thing, residence, when you're giving a given a radiograph, most of you, many of you have a tendency of calling it, this is an x-ray of humorous. Don't call it x-ray is something which is passing through the body. What you're being asked to interpret is a radiograph or an x-ray film. So get into the habit of practicing saying the word radiograph, an x-ray film, rather than this is an x-ray of the hand or x-ray of the femur. This is something very important for students. Now, if the x-ray passes right through the structure, then what we get is a black thing over here. So air on one side. And if it is not going at all, then it is completely white and metal. And in between are the other structures, fat, soft tissue bone, through which there is differential attenuation of x-rays. Look at this gray and this gray, fat and soft tissue. They are hardly, the contrast resolution is very poor because attenuation difference of x-rays through fat and soft tissue is very poor in a radiograph. Let's see now with an example. This is a x-ray radiograph of a shoulder with part of the chest. So over here, this part is the fat. This part is the soft tissue muscle. Now comes the bone out of which this is the cortex and this is the medulla. And over here, if we see adjacent, the air is over here. So to give an idea that this is over here, the radiograph is, the x-ray beam is right passing through. So this is black and over here we have a prosthesis. So in one film, I have shown you all the densities that can be studied. Fat, soft tissue, bone, air, metal, okay? So next question. What parts of a bone can we study in a radiograph? Coming to this, parts of a muscular skeleton system. What are the parts of a muscular skeleton system? Bones, ligaments, tendons, muscles, cartilage, synovium, nerve and blood vessels. And what does radiograph meant for? Is it meant for everything? No, it is meant to see mainly the bones. Ligaments, tendons, muscles, cartilage, synovium, these cannot be clearly delineated in a radiograph and we have to choose some other modality. And obviously the modality of choice as we all know is MRI. Now, out of the bone, what are the parts of the bone which can satisfactorily be dealt with radiograph? For that, let us see what are the parts of a long bone? The outermost covering is the periosteum, which is a fibrocollagenous structure, tightly hugging the compact bone just underneath. Why is it called compact or cortical bone? Because the osteocytes are very closely packed with hardly any space between. After periosteum and cortex comes the spongy or the cancellous or the medullary bone, which is nothing but supporting the bone matrix in which the bone marrow lies. Now, is radiograph going to show abnormalities in all the structures of the bones? No, periosteum, yes, cortical bone, yes, cancellous bone, yes, but sorry, bone marrow is not well seen on radiograph and we need MR for clear depiction of bone marrow, edema or infiltration, et cetera. So this is an example of a patient with a knee injury with acute pain, the radiograph looks pretty much unremarkable but when you see the corresponding MR, look at this bone contusion edema. Can it be understood here at all? No, so this is just to give you an example that marrow imaging is not in bone radiograph. So when you suspect that, don't just talk to this, you should as a radiologist know what to advise for next. Coming to the other structures, as I said, periosteum is a tight fibrocollaginous structure entirely around the long bone but do we see a normal periosteum? No, it is so tight that it's not seen. When is it seen? When there is a bone insult? Within 10 to 21 days, what develops is a periosteal reaction. This is when the periosteum gets elevated from the underlying bone and this is when the periosteum is visible. And depending on the pattern, like this, if it is a regular laminated kind of periosteal reaction, we will know that we are probably dealing with a less aggressive type of a pathology. As I said, this lecture is not dealing with any particular pathology but patterns. On the right hand side, if we see a sinister looking condition over here with sunburst kind of periosteal reaction all ill-defined fuzzy like this, so this is probably a more aggressive vision. So depending on the periosteal type or the periosteal reaction type, we can understand of aggressive person and non-aggressive vision. Let us come to next bone cortex. The bone cortex, as we know, lies in between the periosteum and the medulla and the patterns that we recognize in a bone radiograph, the commonest is cortical break or a fracture. Over here, we see a cortical break fracture and over here we see that the fragmented bones are opposed and there is some amount of osteoid tissue trying to unite these fracture ends. So there is some amount of callus formation. So the first radiographic pattern of cortex bone and the most common is fracture. Next, what is a cortical-based lesion? Again, I'm emphasizing, I am not talking about entities, I'm talking about patterns, I'm trying to explain a cortical-based lesion, versus a medullary-based lesion. There's an excellent lecture on bone tumors where you'll have a clear idea about all entities. So now comes the general pattern. So this is a cortical-based lesion because you see this is an intact cortex, this is the medulla and this is the abnormal cortex where the cortex has expanded with a lucency. So this is a cortical-based lesion and an important thing that you must mention when describing a bone pathology against this. Over here, see, this is the bony cortex and this lesion is abutting the cortex. It has not exactly expanded the cortex, but it is abutting the cortex. So this is a juxtacortical lesion. While this is involving the cortex, a cortical-based lesion, this is a juxtacortical lesion. In contrast, finished with cortex, let's see what the medulla is. So as we have said that underneath the cortex, the medulla houses the matrix or rather medulla and matrix can be interchangeably used. What we see in a normal radiograph, we call a normal medulla is because of normal matrix adequate mineralization. This normal medulla appearance is because of adequate mineralization. Whereas on this side, this is an under mineralized matrix because of which the bone has become very soft. The cortex has thinned out. There is a generalized osteopenia and because of the extreme softness of the bone, the bone has bent and this deformity has happened. So a normal matrix, while an under mineralized matrix in conditions like osteomalacia will give this kind of a picture. Coming just as I have talked about cortical-based lesion, here is an example of a medullary-based lesion. Why are we calling a medullary-based lesion? Look at this, the cortex is intact. We see a sclerotic lesion in which area, in the area of the medulla. Similarly, this is a light-ic lesion in the region of the medulla. So these are medullary-based sclerotic lesion and light-ic lesion with an intact cortex. As we had said, we're talking about matrix. We have already seen what a normal matrix looks like, what an under mineralized. There are some other kinds of matrix. Look at this bone. This is a sinister kind of looking medullary-based lesion with bony pattern, osteoid areas within lucency. So this is an osteoid matrix, whereas this rings-and-ups pattern gives us an idea that probably we are dealing with a cartilaginous lesion. So this is nothing but a conroid matrix. So what are the matrixes that we saw? Adequately mineralized, under mineralized, osteoid, and conroid, four radiographic patterns of medullary lesions that we saw. Now, a little bit about cartilage. Cartilage is a very important part of the musculoskeletal system. It can be either hyaline cartilage or fibrocartilage. While the hyaline cartilage is this, along that is the articular cartilage, this is the meniscus, this is a sagittal image of the knee, showing fibrocartilage. But are we seeing this cartilage as beautifully as this in the radiograph? No, cartilage is not seen in radiograph. On the right-hand side is a condition called synovial chondromatosis, which are nothing but actually cartilaginous lube bodies. But why are we seeing in the radiograph? Because there is an element of calcification. There is ossification of the cartilaginous bodies because of which we are seeing it. If they would have remained cartilaginous, we would not have seen in the radiograph, but yes, we would have seen it in an MRI. Again, we see the after-effects of cartilage loss. If there is significant cartilage loss and the bones get opposed, there is joint space loss and secondary sub-cortical sclerosis, sub-chondral sclerosis. So the effect of cartilage loss is seen as this pattern in a case of advanced osteoporosis. So what you have to remember that cartilage, whenever a doctor's clinician is suspecting and wants to see cartilage loss, radiograph is not sufficient, you have to definitely get an MRI done for that same patient. Number three, very important. Whose bone am I seeing? Is it a pediatric patient, adult, geriatric? Why do we have to know? Because the same process, whether it is a mechanism of injury, whether it is an infection, whether it is a new patient will produce different DDs depending on the person involved, whether it's a child, adult versus geriatric. Let's see with examples. Before that, there are few differences between adult and child bone. The anatomical difference, the main talking in terms of long bone, the long bone diaphysis develops from a primary ossification center and the ends of the bone or epiphysis develops from the secondary ossification center. In a child, these two centers are clearly separated by a lucent area of cartilaginous growth plate and the splayed ends of the diaphysis is called metaphysis. Once growth stops and the cartilaginous growth plate fuses, we do not see it anymore in the radiograph. At that time, it is a fully grown bone with only a diaphysis, a metaphysiol end, and yes, the end is the epiphysiol end. So diaphysis, metaphysis and the epiphysiol end, we no longer separate a diaphysis from the epiphysis. Let's see, this is the same femur tibia fibula in a pediatric versus adult bone, whereas on the right side, we can see the growth plate separating the diaphysis and epiphysis. Once there is fusion, we no longer see this growth plate and this has fused. So pediatric versus adult bone, this is the anatomical difference. This is another very important site where I have given this for a purpose. Both are wrist radiograph on the right. Are we seeing any growth plate? No, carpal bones, distal radius ulna, the metacarpals, there is nothing so on contrast on this side, we see that there are still a few growth plates which are unfused in the distal radius, distal ulna, metacarpal heads. So this gives us an idea that we are this side, the wrist belongs to a younger person compared to this. Now when we talk about this, herein comes what I was trying to say, bone age. Now, this is something very important for students. We have to know that we may or many times we can be asked to study the bone age and for that we will be given the wrist radiograph. What you have to remember that the capitate is the earliest bone to come around one, two, three months and along with Hammett, which also comes same term around two to three months. So capitate and Hammett are the only bones which appeared around two to four months of age after which trichotrim comes around two to three years, lunate appears two to four years, then scaphoid, trapezoid, all coming to succession by six years and finally the last bone to appear is pisiform between eight to 12 years. What you have to remember, capitate Hammett is the first two bones to appear and pisiform is the last. You will not only be given radiographs to calculate bone age, there may be spotters where you will be given conditions with delayed bone age and advanced bone age and you may even have a long case or a short case based on that. So don't ignore this, please go through Gullich and Pile and a little brief thing is given before going for any exam, please go through bone age and its applications because they come in exams regularly. Now coming to the physiological differences between adult and pediatric bone, osteoid has a low density, it can be bent to a greater extent because of excessive collagen, the outer covering is strong but loosely attached and the muscles directly arise from periosteum. Now, let's see the effect of trauma. While in a pediatric bone, there is more chance of a diastatic fracture with the fracture line going along the sutures, just widening it but in a more brittle bone in a same mechanism of injury probably would cause a parietal bone fracture not conforming to the sutural line but going right through the suture like this. So pediatric bone injury has a tendency of sutural diastasis unlike adult bones because of the elasticity of the bone. Similarly long bones while the adult bones being more brutal will be going for a through and through fracture but a very strong injury would cause just bending of one cortex and a unicortical break on the other side because of the excessive collagen, this is nothing but a grain stick fracture. So this is what I was trying to say that the same mechanism of action to produce a different picture in pediatric versus adult bones because of the physiological difference in the bones, anatomical and physiological difference in the bones. In this example, I am trying to give an example of generalized osteopenia in an elderly patient with a trivial trauma causing a fracture like this. Whereas this is a pediatric patient with a focal lucency over here. Rest of the bones are all adequately mineralized with a fracture. So this is an example of a pathological fracture in a child with a benign lytic lesion over here. Whereas this is a generalized osteopenia geriatric patient with a fracture in a similar position just to show you the difference. Similarly, in an adult where the vertebra are all normal in alignment, intensity, height, this is what a fracture line would look like a clear lucency. This is under the superior end plate but in geriatric osteoporotic patient where there is bone softening because of osteopenia, see the different levels of splat is fondile, totally flat, fish vertebra. So this is how an osteoporotic collapse bone looks versus a trauma to an adult bone which is absolutely adequately mineralized in an adult versus geriatric bone. Similarly, neoplastic forces see the growth plate. So this is a pediatric bone. What are we seeing? We see a permeative pattern of ill-defined bone pathology with laminated periosteal reaction. The first thing differential will come in mind is heaving sarcoma. Against this, this is a young adult with a sinister looking kind of a lesion but osteoid matrix will give us an idea that probably we are dealing with osteosarcoma. So the same neoplastic process will give different differentials depending on whether it's a pediatric patient versus an adult. So seeing the age group before writing the report is of utmost importance. Likely, just like an aggressive lesion, this is not a totally fused bone. This is a lytic lesion with a thin sclerotic line occupying the epiphysis and metaphysis. So this is a conroblastoma versus this is a completely fused bone subarticular lytic lesion. We would think more in terms of a giant cell tumor. So just to define, as I said, not into entities just to show you patterns and how you think of different entities depending on the age of the patient. So finished with why age is important, question number four, which bone am I seeing? Are these bones a part of a joint? And if so, are they a part of a large joint or a small joint? So while this is the lower limb, the femur because what are the types of bones? Do you have to know what are the types of bones? One is long bones. So this is a femur, tibia fibrula, humerus, radius ulna. They are flat bones like the skull bones. They may be irregular bones like the vertebral bones. This is a cervical vertebra. This is the lumbar vertebra. They may be short bones like the carpal bones and the tarsal bones, and there may be sesamoid bones. So these are the five types of bones that we have to see. And what you have to remember that they may be part of large joints like elbow joint or shoulder joint and knee joint and hip joint, or they may be part of small joint like the carpal joints or the tarsal joints, the PIP, DIP, et cetera. The more the number of bones in the field of view, your eye has to trace through more, more carefully along more surfaces so that you don't miss out on hairline fractures. So the amount you exert trying to see just knee joint will be definitely less than when you're trying to see a hairline fracture in a wrist which is comprising of so many small bones. This is what I'm trying to say. Now, very important, in the most important question to be answered in my lecture, why have I been asked to study this particular radiograph? What is the clinical suspicion? Still many times I see many residents just given a radiograph, no history given and they just start writing a descriptive thing. Neither will they actually go and find out from the patient or the clinician or even if it's an IP patient does not get the file, it just starts reading and that is absolutely blunderous. You cannot afford to do this. You have to be a clinical radiologist. You have to go through the prescription. Remember, it is the clinician who has actually physically examined the patient and has a clinical suspicion. You are just reading a radiograph. So unless you match these two, your report will never ever be clinically pertinent and closed down DDs, it will be absolutely increasing the confusion. I have made this mnemonic. So once you've gone through the prescription, now what are the entities that they can fall under? C-T-I-I-N-O, citino, congenital, traumatic, infective, inflammatory, neoplastic and rest all others. Others are many. I am just trying to tell you the most important entities coming to congenital. Now in congenital, what are the three things that you have to know? That is a bone which is not supposed to be there is there or a bone is absent where it's supposed to be there or it is in an abnormal shape. Now two things that a resident or a radiologist must know, try to understand that there are some congenital defects which do not need any further effort. You can just write the report. But there are few for which you can either call the patient up to find out about certain clinical history or you get the patient to take a few more radiographs. Let us see this example. What do we see here? We see cervical ribs. You can leave this report saying that bilateral cervical ribs, but if you are a little interested candidate, you will call the patient and ask for some tingling numbness and then you can say that this patient probably has a clinically relevant cervical ribs and I would like to go for whatever angiography, a Doppler, whatever and help your clinician. On the other hand, if you have a biped rib, this does not demand any calling the patient. You can simply write the report. So you have to understand where you can simply write the report and otherwise where you have to call the patient. On the other hand, if you have, if you are reporting this knee and you have seen that there's absent patella, don't just leave to this. Please call the patient and image the pelvis as well as the elbow to look for some entities like this iliac horns, hypoplastic radial head and form a jigsaw puzzle. And yes, this is nail patella syndrome. Now for this residence, you have to read textbooks so that your mind knows that when I see something absent in this part of the bone, I have to call the patient and image this part of the bone. Otherwise you will not know which part to, you can't just irradiate the whole body. So for that, you have to know what are the congenital deformities, which are the systems, the multifocal involvement of congenital deformities. You have to read textbook and then you have to know when to call the patient and image which part. Just one example. For example, this is another one. What is this? This is the bent radius. This is a med lung deformity where the radius is normally growing, but the ulna is growing. Sorry, the ulna is going normally and the radius has stopped and bent. Another important thing for exam going students. You will be given these plates and you will be asked to tell you the differential diagnosis. And one book which should be at your fingertips is Chapman. This is made lungs. What are the causes? Hurlers, infection, trauma, osteocondromatosis, multiple osteomandroid discondustiosis, and turners. They should be at your fingertips. So whenever you see some shepherd's crook deformity, made lung deformity, or an earl and male flask, these differentials should be at your tips and you have to read Chapman thoroughly before going for any exam. Similarly, this is the normal scapula. This is the high-riding scapula with the omow vertebral body. Immediately you know that we can't stop at this, get the patient, image the spine, because you know that probably we are dealing with a clipple fail syndrome and there is chances of blocked vertebra and other vertebral anomalies and you have to see and make that, complete the jigsaw puzzle. Talking about traumatic C-finish T, I am not going to details. Already I've shown you most of the pins. This is a pediatric patient with axial loading, causing mild buckling or a torus fracture. And while because of the increased collagen that I've already shown you, there is a green stick fracture against a through and through fracture in adult bones. This is a trivial trauma generalized osteopenia, how a geriatric patient has this kind of a distal radius fracture and this is hardly any trauma already shown. This is a pathological fracture because of this focal lucensly in an unfused epivysis bone. Now the basic things, there's an excellent lecture coming up by Chaitali on radiographic imaging of trauma. I'm not going to details therefore, but remember I've seen many residents, they just get the AP film, they are not somehow the lateral film is misplaced, they start reporting. That is blunderous, never do it. One thing is marker. Next is if you're imaging fracture dislocation, you cannot start reporting if you don't have both AP and lateral. The two basic orthogonal planes has to be there before you start reporting. If they are not given, don't report. Later on you can do some angulation views and then specific views, but those two views are very important for full characterization of comminution, dislocation, displacement. So never ever report trauma unless you have two orthogonal imaging. And as I've already shown you, dramatic vertebral fracture in an adult bone mineralized and under mineralized collapse, this is how it looks like. Now, C, T, finished. Now, I, I, N, very important. Infection, inflammation, neoplasia. Now, how many of you students actually call the patient, take history and see the lab parameters? I think hardly. You don't have time, you're in given 100 x-rays and you have to cover it. But remember, if you start this practice of matching your radiographic findings with lab parameters and history, you'll find life much more easier. You'll love radiology and your report will also show your love, okay? So, infection, whenever it's an infection of the meteorology, high fever, more systemic manifestations, increased neutrophilic count, raised DSR, CRP, pain stiffness coming early. And if you call the patient, you can see a red swollen joint or whatever, whatever part of the limb or whatever. And if you take the history, this has developed very fast. Against inflammation, there is low grade fever, less systemic manifestations, slightly raised a neutrophilic, but markedly raised CRP. Pain stiffness comes, is very common early morning, comes very slowly, swelling comes early and finally deforming. In any of these cases, you, the, while the systemic manifestations are more against this neoplasia, the systemic manifestations are relatively less. It is more or less indolent, silent presentation. Lab parameters are relatively unremarkable, but skin changes are common patient or many a times presents with pathological fracture. For any of these cases, just as I said, going through history and lab parameters is important. Make it a practice to ask for previous film. Life becomes very easy when you see this pattern is present in your present radiograph, but not there. This helps you to lower down reduced ditties a lot. So coming to infective, earliest infection may just show nothing, but soft tissue swelling. And if you correlate face history and clinical parameters, you can tell also that this is infective. Gradually, lucency appears, periosteal reaction appears. Again, I'm not going to entities. What I'm trying to say, while acute the periosteal reaction is thin as it becomes more chronic, the sclerosis of the cortex becomes more. This increasing sclerosis decides and tells us that it is going towards a chronic stage. Whereas we can all, many a times in chronic osteomalitis, we can see this radiopic thing within this lucent thing. So involucrum, sequestrum, these all is a spectrum of chronic osteomalitis. So what is the important thing, the take home message that while acute has less of sclerosis, more chronic will have more of sclerosis. Inflammatory, what are the radioactive patterns? There may be joint effusion because of fluid or synovial hypertrophy. There may be periarticular osteopenia. Again, we already have a clinical suspicion because of the lab parameters. And now if we see nicely the radiographans find these erosion, central, paracentral or marginal, then we are probably dealing with an inflammatory pathology, rheumatoid arthritis, joint space loss in osteoarthritis. Gradually also the margins of bones become fuzzy and deformities appear. This is the case of rheumatoid arthritis. So the important radiographic patterns in inflammatory or joint effusion, periarticular osteopenia, joint space loss, erosions, margin definition gradually going and deformities gradually appearing. Now neoplastic, I'm not going to details because there's a detailed lecture by Dr. Sanjayjan, a beautiful lecture on this. All I have to say that the important things that you have to keep in mind is first decide whether this is a bone tumor or bone infection. They often mimic each other. And here, previous plate, clinicals, lab parameters really help you to differentiate. If a tumor, whether cortical based on medullary, I've already told you, whether it is affecting child, adult, cell daily so that your differentials are different, I've already told you, aggressive versus non-aggressive. If there's pathological fracture, if there is soft tissue extension, and what is the next modality of choice, that should come to your mind after seeing the radiograph and should be written, suggested in your report. So not going to details while an aggressive lesion is poorly demarcated, poorly marginated with irregular periosteal reaction, rapid rate of change and non-aggressive is well demarcated with a narrow zone of transition, a solid smooth periosteal reaction, a slow rate of change. So just an example of, see this well defined, we can easily understand this is the pathological area, non-pathological area, but look at this, are we being able to differentiate that this exactly the pathology stops and the normal starts? No, plus there is so much of sinister looking periosteal reaction soft tissue. So just to give you an example of aggressive versus non-aggressive. Now, CTIINO, what are the other things that a radiograph can be given for? Again, your prescription matters. One of the reasons is to locate a foreign body. See this radiopic foreign body over here. Suppose the radiograph is given to you to look for foreign body and you can't see anything. Will you leave it? No. You have to remember that all foreign bodies cannot be seen in a radiograph. Glass foreign body, metallic foreign body, animal bone, yes. But if it's a wooden foreign body, plastic, will you see it? No. So if you are an interested radiologist, you call the patient, ask him, he will say that, yes, there was a bony piece that entered. Take the patient to the sonology room and see and you can well demarcate a wooden foreign body. So you have to know when to take it up, exert a little more, deal with the patient and do a little more to help the clinician. Last question and very important, I have finished the bones and leave it. That's not what it's supposed to be like. What is penumbra? Penumbra is outside of the shadow. So when we finish with the bones, please have a clear look into all the soft tissue structures. They often give you a lot of important hints, probably what you're dealing with. Let me give you some examples. This is a bone infection, but if we see the penumbra, we'll see this linear lucency is gas. So we are probably dealing with an infection where you're gas producing organism. This is often we see that calcified this thing, but don't just ignore this. Please document in your report. If you are reporting a radiograph, which the patient is supposed to go for a knee replacement, per se, and you see this, suggest a Doppler. You never know this chronically thrombus, maybe it's a vessel, maybe holding a thrombus and after the OT, the thrombus may suddenly get dislodged and then after the TKR is done, the patient develops black fingers. So the outcome of the patient may change if you stress on things in the penumbra region. Similarly, bones look fine, but look at the calcific density. This is nothing but calcification in the supraspinatus tendon and so a calcific tendonitis comes into mind. Again, over here we've finished with the bones, but we see calcific density over here in the region of the meniscus. So this is meniscus calcification, probably we're dealing with ocarinosis. So by penumbra, I mean those areas outside the bones or those areas which should not be missed before you finish the report. Like calcified lymph nodes over here or venous plebules, they are all coming in the penumbra region that is a soft tissue region. This is the myositis ossificans outside the bones in a post-TKR patient. So to recapitulate, what are the things we show? Now this is the same slide, the initial one was very colorful. I really don't know whether you all have gone to sleep or whether you are feeling very dull and gray like a more practical bone radiograph. So what are the things that I talked of? What are the things? So this is the recap points. So what are the densities we see in our radiograph? Which parts of the musculoskeletal system is can we see in the bone radiograph? Plus which are parts of the bone we can see in a bone radiograph, which we cannot. Differentiating pathologies because of the, by age of a patient, what are the types of bones we commonly see and very important, the practice of going through prescription, communicating with the clinician and patient is a must and never to overlook the areas beyond the bones. I finished my lecture with two cases. This was my FRCF final exam case. The quality of radiograph in the main exam was much more, but this sorry for the quality, but I want you to just get the essence. This was given and in exams like these you just have to go on speaking. You are not given time to stay quiet and see, try to find out. So you have to go on speaking. So since this is a X-ray based, a bone based lecture, there is nothing much in the bone. So all these bones look pretty good. So when you ask, so what I said, you have to go for the history. This patient is a lymphoma patient who has come with very severe cough, high fever, shortness of breath. Is the lungs showing anything gross? Any gross, nothing. So as I'm explaining that nothing is there, this, this, this, go to the penumbra region. Look at this soft tissue swelling in the axilla. So as I said, lymphoma patient and this penumbra shows some pathology. This is the importance of looking at the penumbra region before calling it NAD. So students, when you're reading a radiograph in front of examiner already in a stressed condition, if you follow a protocol, if you don't miss out seeing the penumbra, you'll never miss it. However stressed you are during the exam, you will be able to find out the subtle finding. Another example, this patient has come from Odissa with acute knee pain. And the knee radiograph is quite unremarkable. Look at the penumbra. Look at these thin, calcific densities. We call the patient, yes, the patient is to work in a pink firm. And so we have actually made a clinical diagnosis of muscle cystic surfaces. So this is the importance of going through a radiograph, following a format, not forgetting the clinical history, not forgetting the penumbra region. So most of my cases are from my hospital, but because it's an approach-based lecture, many are taken from Google, radio pedias, thank you team radiologists and all my viewers, I would like you to tell you to be a part of all our masterclass series, our buzz series, RADBUS, the MRI update coming up and please be a part of our regular YouTube channel which has crossed more than 53 case subscribers. Thanks to all of you. Thank you for your support. Because I am, this is running against time, I will answer my questions in the chat box over to Vineet for the next lecture. Yeah, thank you ma'am. Yeah, there are a few queries in the chat box, please have a look. I'll answer them over there. Yeah, our next speaker is Dr. Chetali Parik.