 Hi everyone, this is Dr. Srijita Ghosh from Apollo Glenegals Hospital, Kolkata. Welcome everybody to today's session. Now, as we all know, we have covered an extensive MRI shoulder masterclass where we've discussed the rotator cuff anatomy, MRI protocols and techniques of shoulder imaging, a detailed lecture of rotator cuff tear and what exactly an orthopod wants in a perfect MRI report, MRI instability and accession of good cases. Today, our area of discussion is about a specific area in the anterior superior aspect of shoulder called the rotator interval, which is relatively less understood by radiologists and orthopedic surgeons. Before I go into details of the lecture, I'll tell you a few practical points that a radiologist needs to know. First of all, two questions come into mind. Why do we at all have to know about the region? Secondly, why is it called so complex? Answering the first question, persistent nagging pain of the shoulder is a very depressive condition for patients and equally challenging for the treating orthopedic surgeon who is puzzled as to what to do next, how to bring about the cure. Herein lies the role of a radiologist. Why? Because rotator interval structures are well known cause of pathological chronic nagging pain and as radiologists, if we can find it out in our report and tell our orthopedic colleagues, it will benefit huge number of patients. Not only that, our MRI interpretation may help the orthopedician to relook into their diagnosis and find out the solution. Secondly, why is it so complex? That is because of the complex anatomy of not only the capsule ligament structures here, but also because they are very small and delineating it is quite difficult. Let us go into the details of the lecture. Now let us come to the tutorial proper to see the pictorial depiction of what I told you just now. First we will talk about the anatomy of the rotator interval. Rotator interval is a triangular shaped space in the anterior superior aspect of the shoulder bounded by the coracoid process at the base. The superior border is actually formed by the supraspinatus anterior border and the inferior border is formed by the subscapularis superior border. So what did I say? This triangular space bounded by coracoid process, supraspinatus anterior border, subscapularis superior border forms the boundaries of the rotator interval. The rotator interval capsule is reinforced by two important structures that we have to know. The coraco-humeral ligament externally and internally by the superior glenohumeral ligament. So the coraco-humeral ligament starts as the name suggests from the coracoid process and inserts on either side of the bicepital groove keeping the long head of the biceps in position. And superior glenohumeral ligament on the other hand starts from the superior pole of the glenoid and merges to form the biceps pulley as we will see and discuss later. Two important things that we have to know that this coraco-humeral ligament has two slips before it ends. A medial slip which blends with the SGHL and finally to the subscapularis and the lateral slips which has extensions to the anterior margin of supraspinatus. So what do we have to remember that the coraco-humeral ligament has extensions and it joins part of the subscapularis and also part of the supraspinatus. So any tear that will involve supraspinatus or the subscapularis will probably extend into the biceps pulley. This is why this explanation is required. Let's see how these ligaments look on MRI. They look like jet black structures, hypo intent structures. What is this? This is the coracoid process. This is the humeral head. This is the supraspinatus muscle belly. This is the multi-pinate structure, the subscapularis. And this jet black structure extending from the coracoid process to the humeral head over here is the coraco-humeral ligament forming the superior water reinforcing the superior aspect of the rotator interval. So the coraco-humeral ligament. Now we come to the superior glenohumeral ligament which is actually seen in the topmost cuts in the axial sequence as we see here like this and this is the intraarticular biceps. Once model to show you the space again, this is the rotator interval, the triangular space which is bordered by the coracoid process. The supraspinatus above and the subscapularis below. This is the biceps tendon traversing through it. Another model showing you the same area, coracoid process, supraspinatus, subscapularis. This is the triangular area and what are the main contents that we are seeing over here? The biceps puli which is kind of traversing in between the coraco-humeral ligament above and the superior glenohumeral ligament below. The details of which we will come to later. Another picture of the contents showing the biceps originating from its intraarticular position traversing through a capsule ligament structure coming out. This is the rotator interval region between the supraspinatus above and the subscapularis below. This is one picture which will repeatedly come for our understanding. This is the biceps tendon in the bicepital group. This structure above is the coraco-humeral ligament and this structure below is the superior glenohumeral ligament. The coraco-humeral ligament is attached to the supraspinatus laterally whereas medially it is attached to the SGHL forming a complex which in turn is connected to the subscapularis. This picture will be described over and over again why we will understand very soon. We have to remember that all these structures in this area are very small structures and they require high spatial resolution. This is optimized by strong gradients, surface coils, high field strength scanners. PD-FATSAT and non-FATSAT sequences are used. Oblique sagittal parallel to plane of glenoid is best. Axial cuts show the biceps fully complex nicely. So, let's come to the MR appearance of rotator interval. This is the coronal section in a PD non-FATSAT sequence. This is the clavicle, the deltoid over here. This is the coracoid process. This is the supraspinatus which would be traversing like this. This is the humeral head. This is the subscapularis. This is the subscapularis muscle and this is the superior border of the subscapularis. And so in coronal section our area concerned is this area between the coracoid process. The supraspinatus would be coming like this from above and the subscapularis superior border is over here as we see. See the structures nicely in a sagittal plane. This is the supraspinatus muscle. This is the humeral head. This are the multi-pinate structure, the subscapularis. This is the coracoid. This black structure is the coraco-humeral ligament. This is the biceps tendon. And beside it this structure is the superior glenohumeral ligament. I will revise the coracoid process, supraspinatus, subscapularis forming the rotator interval which is reinforced superiorly by the coraco-humeral ligament and inferiorly by the superior glenohumeral ligament and its main constituent seen here is the biceps over here. In the axial section in the topmost we see the intraticular biceps nicely over here. One look at the arthroscopic picture of how a rotator interval looks like. This is the benoid. This is the head of the humanus. This is the long head of the biceps and this region is what is the rotator interval. This is one area where the rotator calf does not reinforce the capsule. Along with this area there is another area which is the axillary recess. These are the areas which are not reinforced by the rotator calf. Another picture of the rotator interval, the biceps over here going within the pulley. This is the bony glenoid and this is the head of the humerus. This is the subscapularis. So, this finishes the rotator interval anatomy. Now to show the biceps pulley anatomy. This image is of utmost importance and will be repeated by many times why you will understand later when we discuss the pathology. This is the biceps tendon. This is the supraspinatus tendon. This is the CHL over here. This is the biceps tendon. This is the SGHL in the under surface of the tendon. Both these two ligaments have a communication with the subscapularis over here. So, the biceps pulley is a capsule ligament structure surrounding the long head of the biceps keeping it in place within the groove. In upper position, this biceps pulley prevents medial subluxation of the biceps tendon. This is the biomechanics of the pulley. The long head of the biceps originates intraarticulary from the supraglenoid tubercle of scapula and the superior labrum. After originating, the disposition of the structures is as follows. The SGHL and biceps are one beside the other and the coraco-humory ligament is above. As we progress distally, we find that the SGHL comes to the under surface of the biceps tendon. This is called the T-junction and the coraco-humory ligament remains above. Further distally, the biceps tendon is completely surrounded by CHL above and the SGHL below. Let us recap this one by one. This is the MRI picture showing the biceps tendon. This is the SGHL and this is the CHL covering it. So, the biceps tendon, SGHL and CHL is the first part of the description of the pulley. Next is the T-junction when the CHL is seen like this covering the biceps tendon and the SGHL has started coming under the under surface of the biceps tendon. So, the biceps tendon, the SGHL forms a slip going underneath it and the CHL remains above. Finally, we have the biceps tendon in the center and above is the CHL and below is the SGHL. The biceps tendon, the SGHL underneath and the CHL above. This is how a normal arthroscopic view shows the biceps tendon entering into the biceps pulley. This is the head of the humerus. This is the subscapularis area. A pristine looking biceps, normal biceps entering into the biceps pulley. This is the head of the humerus. This is the SGHL. This is the subscapularis. Now, one by one, we will be discussing about the biceps pulley lesions. The biceps pulley tears, rotator synovitis. Very briefly about anterior superior impingement. We will show you a few cases of biceps tendinosis. And I will just discuss in one line about slap tear extending into biceps and laxed rotator interval with instability. Biceps pulley lesions are as a result of acute traumatic injuries, repetitive stress, anterior superior rotator cuff tear or degenerative changes. Again, we see this picture and adjust a quick recap before it comes to the tear. The supraspinatus biceps tendon in the group subscapularis. The coracohumeral ligament above the tendon, the SGHL below the tendon, the CHL laterally is attached to the supraspinatus tendon. Immediately it converges with the SGHL and together this complex is attached to the subscapularis tendon. Why I am repeatedly hammering is we will understand that tear of important rotator cuff muscles like this can cause a biceps pulley tear and instability of the biceps tendon. As I have already told you, when the biceps tendon can be manipulated out of its position as it enters the biceps group without passing over the greater or lesser tuberosity, it is called subluxation. On the other hand, if it can be manipulated out of its position, completely out of the greater or lesser tuberosity, it passes over the greater or lesser tuberosity that is when it be called a dislocation. This is a Habermeia classification classifying the tear into four times. Now, you will understand the importance why I showed you that diagram so many times. This is the biceps tendon, this is the humeral head, this is the supraspinatus muscle, this is the subscapularis muscle, this is the coracogumeral ligament, this is the SGHL. Isolated SGHL tear is the first category where we just find mild medial subluxation of the biceps tendon. In the second category, along with this SGHL tear, there is a supraspinatus tear. Here the biceps tendon is slightly dislocated anteriorly. Next, this is an SGHL lesion along with the subscapularis lesion and the biceps tendon is dislocated into the subscapularis. Finally, this is a massive tear not only of the SGHL but the supraspinatus and subscapularis and the tendon is completely dislocated out of the groove. There are further classifications also but ultimately what I had told you before is we have to find out whether it is medially subluxed or whether it is out of the groove. Coming to a few cases. Case number one, this is the supraspinatus muscle, this is the subscapularis, this is the humeral head, this is the coracoid presses, this is the biceps tendon. We expect the normal SGHL here but where is it? It is not there. Also the superior aspect of the subscapularis looks relatively hibernated. Another picture, we are not seeing the SGHL where it is supposed to be. This is the supraspinatus, subscapularis, biceps tendon, SGHL not in place. Lot of fluid in this region. The SGHL is torn. If you go back to the lecture in the beginning part, you can view how a normal SGHL looks like then you will understand this is a pathological SGHL. Coraco-humeral ligament is supposed to be a jet black structure, traversing something like this. But look at this, over here there is a breach over here. Superior aspect of the subscapularis is not intact. We are seeing a small tear over here. These are examples of small tears of the biceps pulley. Again another example where the normal biceps tendon and SGHL as shown in the normal case here the SGHL is not existing. Neither are we seeing the coraco-humeral ligament properly. Atroscopically these patients may show a very lax biceps which can be easily suplexed. Another picture where the biceps is pathological and is partially being cut. This is the area of the rotator interval. Now coming to graver injuries. This is the normal anatomy showing the humeral head. The glenoid. This is the infraspinatus tendon, the subscapularis tendon, axial section with the bicepital groove and the normal biceps. But this is an abnormal subscapularis, maybe a significant case of tendinosis and tear and a medially subluxed tendon which is still not out of the groove remaining within the groove. But in this case there is a high rate of subscapularis and the tendon is out. The biceps tendon is out of the groove here. Here it is not only out, it is way away from where it's supposed to be at completely dislocated biceps. Another completely dislocated biceps. In this case only there was a torn SGHL seen nicely here. Another case of dislocated biceps with torn subscapularis tendon. This is an early biceps subluxation with a subscapularis delaminating tear. This patient also had a associated supraspinatus tear. A high grade undersurface tear of subscapularis with biceps tendon medial subluxation. This is a biceps where it is just perched over the medial lip of the groove with undersurface tear of the subscapularis. The biceps tendon in this has gone into the substance of the subscapularis, football and quarterback appearance. Anthroscopic view of such massive injury showing torn supraspinatus, glenoid here, the torn subscapularis. This would be the original site of the biceps but look where it is lying completely subluxed. Biceps tendonosis is inflammation of the biceps tendon. It may be primarily due to structural abnormalities of the biceparyl groove or secondary to cuff impingement, rotator cuff. What we see is change in tendon diameter, change in abnormal signal, whether it is tendonosis or there is an associated tear where there is proper fluid signal within the biceps. Fluid along the biceps tendon sheath, we have to remember that some amount of fluid is seen in biceps tendon if there is joint effusion but if we see repeated cases then our eyes will be tuned to understand that this fluid around the biceps is abnormal and this is normal. A normal biceps tendon as seen in axial view, an abnormal signal in the biceps tendon, suggestive of tendonosis, extremely thickened tendon with intra-substance signal changes. Now we come to another entity called rotator synovitis or adhesive capsulitis. This is yet another condition causing nagging, debilitating pain and gradual restriction of movement of the patient leading to severe, severe depression and problem. This is commonly known as frozen shoulder by most of the people. Why rotator interval is important? Because the earliest sign of this disease is seen as edema of the rotator interval. In very later cases we see thickened coraco-humeral ligament and joint capsule with obliteration of fat under the coracoid process. This is a normal signal intensity of the rotator interval but this is a mildly thickened coraco-humeral ligament with fluid underneath. Significant rotator synovitis, significant inflammation in this region, grossly thickened coraco-humeral ligament here along with grossly thickened inferior glen-humeral ligament here. Rotator interval synovitis with extreme inflammation over here along with sabacromial bursitis. Another case of rotator interval synovitis with thickened biceps over here, thickened coraco-humeral ligament and advanced case of adhesive capsulitis and arthroscopic view showing angry inflamed synovium over here. Now very briefly few lines about anterior superior impingement. This is a condition where there is a pulley lesion leading to biceps instability. Deep surface of subscapularis tendon along with the pulley lesion will impinge against the anterior superior glenoid ring in a position of horizontal adduction and internal rotation of arm. So deep surface stare of subscapularis dislocated biceps impinging on the anterior superior labrum causing anterior superior labral tear. Two other pathologies I will just add two lines. One is lax capsule. Now in multi-direction and instability is a condition where orthopedic surgeons can examine and see extremely lax capsule with sulcus sign positive which indicates that the lax rotator interval capsule must be present. The structures of the rotator interval prevent inferior glen-humeral translation because they maintain negative glen-humeral joint pressure. But if the capsule is very lax then we may not be able to see on plain MRI but our orthopedic colleagues will definitely feel a lax capsule. In those cases we may have to perform an MR-arthogram to see ballooning of the capsule in two specific areas. Auxiliary recess and the rotator interval areas. These areas the capsule is not reinforced by the rotator cuff muscles. But nowadays MR-arthogram is hardly practiced. A 3 tesla MR and clinical examination suffices. Lastly the slap tears are of many types. The labral tear extending into the biceps or the type 4 tears fall under part of pathology of the rotator interval. I am not going into details in this tutorial. So to summarize what did we learn? We learnt about the rotator interval anatomy how it looks on MRI the biceps puli anatomy the various types of puli tears how sub-scapularies and supra-spinatus two important muscle tears can cause biceps puli tears leading to unstable biceps. We learnt why the biceps is important a little about biceps tendinopathy adhesive capsulitis and tyrosine period impingement and as radiologist we learnt that proper interpretation can help solve nagging pain which is the most important complaint that the patient comes with when they have pathology in the structure. So to conclude several pathological problems can be resolved very smoothly if there exists a close working liazo between the orthopedician and the radiologist if the MR is done in the correct protocol a special thanks to many people without whom this tutorial would not be possible and finally a big thank you to all the YouTube viewers who are watching this tutorial patiently hope I could do some justice. Thank you very much.