 So, now that we have talked about the normal anatomy, let's start asking ourselves questions. Always look at the history. It's important to know what had happened. Was there a trauma? If so, how long back was the trauma? Is the patient a sports person? Is there some recurrent dislocation or feeling of instability? Know the history. If the primary question is rotator cuff, especially older people, ultrasound may also be enough to look at just rotator cuff tear if that's the question. MR can answer more questions, so let's look at that. Obviously, the first question we want to answer, is there a tear or not? Let's begin with that. Is there a tear? This is how a normal tendon looks on all sequences. It is hypo intense. This is because there is no mobile water protons. The hydrogen protons are tightly bound in the collagen fibers. They are not moving around. They are not giving any signal. So, it looks dark on all the sequences. PD, T1, FATSAC, T2 and some little artifactual signal at this critical zone is fine because of magic angle artifact. Any structure that's at 55 degree. So, the external magnetic field can show abnormal signal and that's artifactual. How do I know it's not real? If it's not showing significant signal abnormality on the T2 image, on the higher RT image, then it's not to be worried about. What happens if I call it as minimal or mild critical zone tendinosis? Nothing. It's not something that's going to need surgical management. When I talk of tendon, this is the footprint. This is the critical zone. This tendon looks abnormal for sure. What do I see? This tendon is thickened significantly and it's showing bright signal. It's no longer dark. But, is it there? No, it's tendinosis. The right term is tendinosis or tendinopathy. We do not want to use tendonitis because there is no inflammation here. So, tendinosis or tendinopathy is the right term. It's not enough to just say tendinosis. You want to say whether it is mild, moderate or severe or advanced. So, here you can see there is advanced critical zone supraspinitis tendinosis. Why this is important? Because when there is severe tendinosis, the internal fibres are all kind of not tightly packed together. Hydrogen protons are moving there giving bright signals. And sometimes these can be as symptomatic as a full thickness tear because the tendon is not really functional and the surgeon may decide what to do based on that. But it's not a tear right now because there is no fluid signal intensity. This is fluid in the joint. It's not that bright. So, this is severe tendinosis. Okay, now is there a tear? Suppose you decide it is a tear. What are the things that I want to talk about? Is it a partial thickness tear or is it a full thickness tear? And what's the location of the tear? Where is the tear located? So, is it a tear along the articular surface? So, just look at this area. The bursal surface fibres here are intact. Articular surface fibres are torn and this is at the footprint. Now, what we should always mention, so it's not enough to say there's a tear. It's not enough to say it's articular surface or footprint tear. What's important? How severe is this tear? How bad is this tear? So, I always like to use the term, take 50%. So, is it more than 50% thickness? Less than 50% thickness? You may say more than 75% thickness or near full thickness when barely few fibres are at that. So, this is something I'll call more than 50% thickness, supraspinatus footprint under surface or articular surface tear. As against that, here now is a tear where you can see the articular surface fibres are intact here. The bursal surface fibres are torn. So, now I would call this, this looks like more than 75% thickness. I would say this more than 75% thickness. Critical zone bursal surface tear. Okay? So, that's what is important. Now, sometimes you can have tears like this, which are interstitial. The tear is all within the substance of the tear. Articular and bursal surface fibres are intact. So, obviously the surgeon cannot see it when he goes in arthroscopically. The arthrogram, if you have done, would not show, there's no contrast going in there. Again, I'll say how much thickness. So, this is more than 50% thickness of the tendon that is involved. So, we need to convey how severe or how bad is something. Most of the partial thickness tears are usually managed conservatively to begin with. Not working, they may give injections ultrasound guided. When it's more than 50% thickness and patient is not responding to conservative management, then surgically would be planned. So, the information that we give has a meaning. And it's very important to answer the right questions. Or is it a full thickness tear? Full thickness tear, very easy to identify. Yes, there's a whole big tear out there. There's no tendon remaining at all. Okay, we know there's a tear. We know whether it's partial or full thickness. What's more important also is to tell the size of the tear. I told you about the thickness but also give the dimension. By dimension, I'm talking of longitudinal dimension and AP dimension. So, this is the same case, more than 50% thickness. Articular surface tear at supraspinatus footprint. And now if I look at the sag, all of this is the infraspinatus. All of this is the supraspinatus. So, this tear is at the anterior footprint because supraspinatus has an AP extent. And I measure this. For example, this may be 5 mm. So, more than 50% thickness, anterior supraspinatus footprint, articular surface tear, measuring 5 mm AP without significant retraction. So, it's barely retracted. This might be maybe just 2 mm. So, no significant retraction or you can say retraction by 2 mm. That's the longitudinal extent. So, there are three things. Thickness is this dimension. How much of the thickness? Longitudinal is this dimension. How long is the tear? AP is this dimension on the sagittal images. And every tear you need to talk about all these three whenever you are talking of a partial thickness tear. Here I have a near full thickness Bursal surface, supraspinatus footprint tear. Also tell how the tendon is. This tendon already shows moderate tendon. And now, this is the infraspinatus. This is the supraspinatus. So, this is at the posterior footprint. This is the AP dimension, maybe 4 mm with about 3 mm retraction. So, this is the information that's required. Sometimes you may have delaminating tear. Tear has started articular surface and then gone interstitial. So, it's important to give this dimension also because the tear is extending all the way. Sometimes it may happen. Superficial fibres are retracted up to this level. Deep fibres are retracted up to this level. Surgeon needs to know both this extent as well as this extent. So, mention those findings. Full thickness tear, which is a complete tear. Entire AP extent torn, entire tendon torn. So, I call it a complete full thickness tear. What is important? How much is the tendon retracted? So, this tendon is retracted up to glenohumeral joint by approximately 4 cm. Or, I may say in some other case, retracted by 1.5 cm up to mid-humeral head or by up to 3 cm up to medial humeral head. It's very important because then the surgeon can decide whether arthroscopic surgery can pull the tendon or is it too much retracted he may not not good prognosis may not want to operate or if he operates he may have to do an open surgery may need to do tendon transfer. Next question. What is happening to the other tendons? Yes, we are all looking at supraspinatus tendons all the time. But, remember other tendons full thickness supraspinatus tear infraspinatus tendon is also torn and retracted here. Here, you can see no supraspinatus tendon at all. Always look at subscapularis because that's the area the arthroscopy surgeon finds it difficult to see. So, he wants to know beforehand what is happening. This is the subscapularis tendon and you can see there is a high grade there. So, again, grade if you want to use the terms we use so be sure your orthopedician knows what you are meaning. By high grade, I mean more than 75% things. Intermediate grade, I mean 50%. And low grade, I mean less than 50%. Or just say the thickness, that's also fine. So, more than 50% thickness under surface tear along the subscapularis and you can see the biceps tendon here. Instead of being here in the groove, it's got dislocated. Whenever you see biceps dislocation, look at subscap tear. Whenever you see subscap tear, look at biceps tendon because the subscap fibres course over the tendon keeping it in place and the pulley I spoke about. Okay? And you can see this patient had supra and infraspinatus tears as well as subscapularis tear. Always look at biceps tendon. Is it enlarged, tendinosed or sometimes you may have no significant healthy remnant at all. It may be chronic tear and there is nothing that you are seeing at all. You need to mention this. Now that there is a tear and you have described all the sizes of it, what are the other things that the surgeon needs to decide what to do? Because everything as I said has a meaning. It's not enough to just say there's a tear, you are right, you are not wrong. But are you helping the surgeon? Maybe not. He wants to know what is the status of the muscle. Now, if the muscle is good for surgery, the person's return to function recovery would be good. If the muscle is atrophic because the patient has had a tear for a long time, the surgeon may still operate but that would be because for pain relief. Not for only the function recovery, he may explain to the patient that we are operating for pain relief. Function, how much of it will be recovered cannot be set for sure because the muscle is already atrophic and it's not contracting well. Look at this sag image. Look at this supraspinatus muscle. This supraspinatus fossa it should be occupying whole. When there is atrophy, obviously it is small. Now there are two things. One is muscle volume loss. When the size is smaller, but there is no fatty infiltration. With physiotherapy, that can still be regained. If you draw a line along coracoid process and the spinoff scapula, supraspinatus should go above it. But once there is all fatty infiltration like this, that muscle is not going to recover no matter what. So remember when you have rotator muscle atrophy. This is advanced atrophy. This is moderate. So there are these classifications. You can use those grades. We use the term mild, moderate, severe. If you want to use gradings depending on how much muscle and fat is there, you can use them. Whenever there is rotator muscle, cuff muscle atrophy, remember either it's denervation or there's a tendon tear. So look for these carefully. Tear is minor. Very often we see the muscle atrophic line. It's asymptomatic and usually not of any significance. What is the status of the cartilage? Okay, there's a tear everything. But because this umbral head is chronically migrated up, touching the acromion, all the cartilage is lost. There is severe cartilage loss. Tendon is retracted here. No point in operating. This is end stage rotator cuff arthropathy. Maybe they might do a reverse shoulder arthropost if the patient has need for that. But repair of the tendon is not going to help in this because the articular cartilage is already gone. Is there impingement? Impingement is not an MRI type. It can be diagnosed only clinically and on ultrasound.