 So today what we are discussing is normal MRI anatomy of the shoulder. In today's session, we'll be discussing about the normal anatomy and the MRI anatomy of shoulder joint, the sequences and planning for any MRI shoulder, how do I read a MRI shoulder scan and the checklist in different planes. For any shoulder joint, these are the normal structures that you need to look at. It's just a list of structures we'll be looking at each one of them in this entire session over the next 15 to 20 minutes. Whenever you do an MRI shoulder, there are two joints that you're going to cover. One is your glenohumeral joint and the other one is your achromoclavicular joint. Now, first we'll concentrate on the glenohumeral joint because that is a more important joint. So it's a ball and socket joint where the ball is nothing but the humeral head and the socket is nothing but the green oil of the scapula. Now if you note, the humeral head or the ball of the joint is larger whereas the socket which is the green oil is a more flattened appearance and because the glenot is more flat and the humerus is more larger, it provides more mobility to the shoulder joint, but this comes at an expense of instability. So in order to provide more stability to the joint, there are soft tissue structures around the joint which help in making the joint stable. So if you'll see, this is your glenoid achromoclavicular surface. Around the glenoid, you have a labrum. Look at this thin purple structure which is the labrum. Then the green structure around it is the capsule and around that you have the rotator cuff tendons. So these are the soft tissue structures around the shoulder joint that help to provide stability to the joint and we need to look at all of these structures in a shoulder scan before labeling it as a normal scan. So whenever you do an MRI shoulder, the sequences that you need to take is a T2 fat saturated coronal sequence. So this is not a particular thing that everyone needs to do but this is what we usually do in a routine practice. You can add and subtract sequences depending upon your personal liking and experience. So first we go for a T2 fat saturated coronal sequence. Now the important thing is the planning of the coronal sequence. So just remember whenever you take a coronal planet on an axial, the planning should not be along the muscle but instead it should be along the tendon. So you can see this jet plaque structure that is your supraspinitis tendon in the axial plane. You need to plan your coronal along the supraspinitis tendon and not along the muscle. So make sure you inform this to your technician. Next sequences that we take is the proton density images in all the three planes. Proton density images, non fat saturated sequences, non fat saturated because they give us a better visualization of the tendons, the small ligaments, labrum, cartilage, everything. And lastly T1 weighted images are not taken in all the scans but conditions where you're suspecting tumors, infections and inflammatory conditions, you need to go for a T1 weighted sequence. Now how to approach an MRI shoulder scan? So always have an approach for any joint that you report. For an MRI shoulder scan, I use the structural approach that is I go structure wise and in that also I use the inside out approach. So first I looked at the innermost structures and then I'll gradually make my way outwards. So first I look at the intraarticular structures that is bone, labrum, cartilage and capsule followed by biceps and rotator interval. Then going further out, you have the rotator cuff, muscles and tendons and the bursae. And last I looked at the AC joint and the neurovascular bundles. Now all of us are aware of the anatomy of the bones. We've been reading them since our first year of MPBS. So I'm not going much into it. What I'm going to discuss are the practical points which are important when you look at the scan. So these are the areas that you need to keep an eye on when you're looking at an MRI shoulder scan. So for humorous look for the hill sacks and reverse hill sacks legions, greater tuberosity fractures. Glenoid look for the bony, bancard and the antero-inferior glenoid bone loss, coropoid process fractures, acromion process fractures. And this one important thing is distal end of clavicle. Important because we usually tend to mist it in the scan because it comes in the periphery of the scan. So make sure to look at the distal end of clavicle because there can be stress fractures and stress edema particularly in weight lifters in the distal end of clavicle. So now let's look at each of these on a normal MRI scan. So this is a coronal proton density, non-fat saturated image. We are going from anterior to posterior. The anterior most structure that you see is this coropoid process along with the short head of bicep stentate. Now as you go posteriorly just make sure currently we are only looking at the bones and nothing else. So as you go posteriorly you begin to see the antero-inferior glenoid. Keep an eye over here for the bancard lesion for the osceus bancard lesion and marrow edema. Then further posteriorly look at the greater tuberosity with the supraspinitis and intraspinitis tendons attached. Avergene fractures are common in this region and please note avergene usually these avergene practice are not displaced. So they are difficult to pick up on x-ray but they can be easily picked up on an MR. Then this is the important thing that I was talking about. Look at the distal end of clavicle because we usually tend to miss this area. Now you will see in this region this grey zone. So the black is the cortex above that there is a grey zone. So this is nothing but your tumoral articular cartilage. This is the glenoid and over here also you can see there is a thin grey zone that is your glenoid articular cartilage. So this area is your subconvial region for the humerus and the glenoid. Keep an eye on this area for subconvial marrow edema and subconvial cystic changes which will happen in venerumural osteoarthrosis. Then as you go further posteriorly in the posterior superior aspect of humeral head look out further for any flattening any marrow edema or any defect which would indicate the hill sac region in a patient with recurrent dislocations. Okay, now let's look at the sagittal image. So we are going from lateral to median and again this is a proton density non-fat saturated image. So you can see these are the tendons. It's a supraspinitis and inpraspinitis tendons and this is nothing but your greater tuberosity. So keep an eye over here for GP fractures as you go inwards or medially look at this region. So if you say this is your acromion process. So this is posterior and this is anterior. So posterior superior humeral head look out for any defects any flattening and marrow edema suggestive of hill sacs lesion. This is the most important sagittal image that you can get for a patient with anterior instability. So this is nothing but the N face view of the glenol or the glenol articular surface. The plaque thing around it that you can see is the labrum. So this particular image is very important even for an orthopore. You need to look out for an anterior glenol bone loss or any auspicious bankard lesion. You can use your best fit circle method in this region where you draw a circle along the posterior and inferior cortex of glenol and it should pass through the anterior cortex. If it does not pass, then it indicates that there is an anterior glenol bone loss. So just remember to get this section. This is really important section. The next thing is your porcupine process. Porcupine process fractures is particularly important in patients with anterior instability because whenever there is an anterior glenol bone loss which is significant, the orthopore will use this porcupine process and put it here which is called as a lethargic procedure. For that, he needs an intact porcupine process. So just make sure that there are no fractures in the porcupine process. Now let us look at the HU scan. So you have a distal end of clavicle which is the superior most image. Then what you see is your atromial clavicular joint. So this is your atromial process, distal end of clavicle and this is the joint space. Inferiorly when you go here you can see this is the superior sections of the humeral head and this is the posterior aspect. So you can see there is a curvature. It's actually a pretty round structure. Look for any flattening. Look for a wedge shape defect in this region and marrow edema which will indicate a hill sacs region. Further Inferiorly, look for the hill sacs region. So just remember when you go further inferiorly there is a normal flattening in the posterior superior in the posterior humeral head. So this should not be labeled as a hill sacs region. Hill sacs region is only when it is in the superior sections but when you go inferiorly this flattening is normal. Similarly here we should look out for any again any marrow edema and the defect which would indicate a reverse hill sacs region. Again inferiorly you will see there is a flattening in this region. This flattening is normal and should not be labeled as a hill sacs region. As you go further inferiorly, look at the anterior inferior glenoid for any osceus-bankart lesion for any glenoid bone loss and marrow edema. So these are the structures which are particularly important when you look at the bones. Now let's go to the labrum. So as I have told you the glenoid socket is a flattened one and in order to provide some contability to it there is a labrum around it. So this purple structure is your labrum and this blue is nothing but the glenoid articular surface. Now, whenever you describe an April tear, you need to describe the exact extent of the tear. For this you can use something called as the clock position. So the superior one is your 12 o'clock position, the inferior or 6 o'clock position. The place where the biceps goes, here you can say the biceps is going this way, that's your anterior. Here you can also make out that this is your acronym process, so this is a posterior aspect. So anterior equator, equator is nothing but the glenoid vein, so anterior equator is 3 o'clock position and posterior is 9 o'clock position. Now there is some confusion sometimes in the nomenclature regarding the 3 and 9 o'clock position. So in order to be completely crystal clear, what we need to do is you can also write about the quadrant in which the labrum tear is present. So you can divide your labrum into like an X, so this is your superior quadrant, inferior quadrant, anterior and posterior quadrant and one more line which you can add is a horizontal line joining the equator, the anterior equator and the posterior equator, so now the anterior labrum is further divided into anterior superior and anterior inferior labrum and the posterior labrum is further divided into posterior superior and posterior inferior. So whenever you describe a labrum tear, make sure to tell which quadrant it is involving and also if you want you can give the clock of the tear, so you can use both of this together but please make sure to use the quadrant because it's more crystal clear. Now whenever you look at the labrum, the superior labrum is best thing on a mid-peron image, so this and just remember all the labrum has a triangular appearance in whatever plane you look at it, usually it's a triangular appearance. So this is your superior labrum, this smaller one is your inferior labrum and the anterior and posterior labrum are best thing on the ancient images, so this is your anterior labrum and this is your posterior labrum. Okay, so now another structure which reinforces or provides stability to the joint is the capsule around the joint and important to note is anteriorly this capsule is thickened at places to form the glenohumeral ligaments, so you have the superior glenohumeral ligament, middle glenohumeral ligament and inferior glenohumeral ligament. So these are present anteriorly, inferior glenohumeral ligament also has a posterior band which is present posterior. So now let us look at the labrum and the glenohumeral ligaments together on an axial scan. So this is an axial PD non-pat saturated image and this is the topmost section. So what you see is your superior labrum over here and you can see a thin flimsy structure that is coming out of the superior glenoid. This is nothing but your superior glenohumeral ligament. This ligament is better seen on a surgical image and we'll have a look at it later. Further when you go inferiorly, the structure that you see here, you can see two structures. So the triangular structure, this one is your labrum, okay? This triangular structure is your labrum. So this is the anterior labrum. This is the posterior labrum. Another black structure that you see over here, this is a thickening of the capsule which is nothing but the medial glenohumeral ligament. Now one more thing that I want you guys to note is this. You can see there is a cleft. So there is one thing, I'll just go a step back. Yeah, so you can see there is no cleft over here, but there is a discreet cleft over here. This should not be labelled as a tear. This is a common normal variant called as sublabel foramen. It is present in the anterior superior quadrant. Unless you see a tear extending anteriorly inferiorly or across the superior labrum into posterior superior quadrant, do not label this as a tear. This is just a sublabel foramen. And another normal variant is where this MGHL will be more thickened and you won't see a triangular labrum over here. So you will see the posterior triangle but not the anterior superior triangle and that is nothing but the G4 complex and added. So here now as you go inferiorly, this thing is your anterior inferior labrum. This is your posterior inferior labrum and another thickening which you see more lateral to the anterior inferior labrum. This is nothing but your inferior genitalumeral ligament. And here you can see that the capsule is thin. So the capsule is thin but this is more thickened capsule which is nothing but the genitalumeral ligament. Now this is just to show you the difference between the normal labrum and an abnormal labrum. So this is a normal labrum. Normally there should not be a fluid signal intensity between the labrum and the glenoid bone and the glenoid cartilage. So this is normal. Here you can see there is a discrete fluid signal intensity which is passing between the labrum and the underlying glenoid cartilage. So this is nothing but a labral tear. Now as I told you, SGHL or the superior galenumeral ligament is better seen on a sagittal image. It's a thin flimsy structure which will arise from the glenoid. We will further discuss this ligament when we discuss the rotator interval. So for now you can just keep in mind that this is how SGHL looks like. And even your MGHL and IgHL can be seen on a sagittal image particularly in a patient who has joint diffusion. So whenever there is some joint diffusion, you will appreciate. You can see on this diagrammatic image. So this thing is the capsule. You can see there is thickening. So this is SGHL, MGHL and IgHL anterior band. And you can correlate this image over here. So you can see this is your thin capsule. In this region it is thickened jet black structure. That is your MGHL and below it is another thickened jet black structure, which is your IgHL. So this is how you can look at these ligaments even in a patient with joint diffusion. Now what we need to look at is biceps and rotator interval. Now there are biceps can be divided into three parts. So you have a horizontal segment which runs about the human head, then you have the pulley where it turns to form the vertical portion and the vertical portion runs in the bicepital group. Biceps pulley is important because it stabilizes the biceps tendon in the region of the turning of the pulley and in the bicepital group. So it prevents biceps dislocation and biceps pulley comprises of THL that is coraco-humeral ligament, superior glenoyumeral ligament and superior subscapularis tendon. Rotator interval is present between three structures which we will discuss when we see the scan. So this is your biceps tendon. Okay. This is your short head of biceps and this is your long head of biceps. This is the horizontal portion of the biceps which arises from the supra-glenoid tubercle. Then it will turn over here. So this is the region of the pulley and then this is the vertical portion which is running in the bicepital group. So this is your lesser tuberosity, this is your greater tuberosity and this is the bicepital groove. And across this bicepital groove you have something called as a transverse-humeral ligament which is nothing but a slip from the subscapularis tendon which stabilizes the tendon within the bicepital groove. Now important thing to understand is the biceps pulley. So you have the coracoid process. From the coracoid process there is a ligament which comes out which is called as coraco-humeral ligament. So it comes from the coracoid process and goes and attaches to the humerus near to the bicepital groove. So this is the superficial structure. Then you will remove the coraco-humeral ligament deep to it you will find the bicep tendon traversing. So the red colored structure is the bicep tendon and you will find the superior general ligament which is a green colored structure. So immediately it is just alongside the bicep tendon but as it goes naturally it goes deep to the or it goes inferior to the bicep tendon. So now we look at the actual MRI images. We are going from again anterior to posterior on a coronal image. So first thing that you are seeing over here is the subscapularis tendon. Now as you go posteriorly you can see your bicep tendon over here. This is the bicep tendon in the bicepital groove and this is the pulley region. Further on this is your horizontal portion of the bicep tendon above it is the supraspinitis tendon below it is the bicep tendon. Here you can see the bicep tendon and this it goes and attaches to the labrum the superior labrum. So this is nothing but the bicep's labrum junction. This is important in case of tears slag tears can involve the bicep's labrum junction. So you should look at this properly. Next thing that the woman discuss about is the rotator interval. So this is a sagittal image which is passing through the level of the laryngeal joint line. And rotator interval is nothing but a triangular space which is present in the anterior superior aspect of the shoulder between coropoid process, subscapularis muscle and the supraspinitis muscle. So this triangular structure is the rotator interval. The main content of the rotator interval is factor. Now this is important and therefore your proton density images, non-fat saturated images have a rule because fat will appear bright whenever there is adhesive capsulitis there will be scarring with some amount of edema in the rotator interval and that scarring is easily picked up on a proton density non-fat saturated image whereas it is difficult to pick up on a fat saturated image. So unless there is going to be an edema you are going to miss this finding completely on a fat saturated image. Hence proton density non-fat saturated images are really important for shoulder image. So this is the fat region. If you see scarring in this region you can think in terms of adhesive capsulitis. Now the next structure that is arising. This is your coracal humor and liquor. So as I told you it arises from the coropoid process goes to the humorous and attaches near the bicepital through. So this is your triangular rotator interval. The coracal humor and ligament reinforces the roof of the rotator interval and the contents of the rotator interval is this thing structure which you've seen before also which is the superior glenuleuron ligament and bicep tendon in this region. So SGHL and bicep tendon are the contents of the rotator interval. Now as you go naturally here you can see that the relation is bicep tendon and SGHL are next to each other with CHL forming the roof. Now as you go further naturally you can appreciate this oval structure is your bicep tendon here you can see this is your SGHL this is your SGHL and here you can see it is trying to go beneath there is a curve it is trying to go beneath the bicep tendon. So here you have CHL on the top the bicep tendon and SGHL which is trying to go beneath and now in the region of the turning of the bicep tendon you have this CHL on the top you have the bicep tendon and the SGHL is going beneath it. Now this bicep scully region is particularly important whenever there is tear of the sub scapularis or tear of the SGHL it will result into dislocation. There are different types of dislocation of bicep tendon so it's a different classification which you can look at it later. Now let us look at the most important thing that is the rotator calf tendons. So we all know that there are four rotator calf muscles and tendons so the superior is a supra spinatus anteriorly you have the sub scapularis. The third one is the infraspinatus which is exactly posteriorly so since this is a 2D image I am not able to show it here so posteriorly you have the infraspinatus and posteriorly inferiorly this is the 3D spinal tendon. Now this is a sagittal image to show you the muscles so you can see this is the coropod process so this is anterior. So supra spinatus fossa has the supra spinatus muscle anteriorly is the sub scapularis muscle posterior superiorly you have the infraspinatus muscle and posteriorly inferiorly that is the 3D spinal muscle. Now let us look at the tendons individually so this is a sagittal image at the level of the humeral head where you can appreciate all the tendons so this is a point to note that a sagittal image you can evaluate all the tendons together so the anterior tendon is your sub scapularis tendon if you see there are multiple small jet plaque structures inside so it's a multi-pinate tendon not a single tendon it's a multi-pinate tendon but on a diagrammatic image I've actually drawn it as two separate structures so this is because the superior sub scapularis and the inferior sub scapularis are functionally separated so superior sub scapularis is a functionally different one and inferior is a functionally different one but anatomically they look simple and your superior sub scapularis is particularly important because that is more prone to tears. The next what you've seen over here this is your biceps tendon and then you have the supraspinatus and infraspinatus tendon so the first one is the supraspinatus tendon the green structure is your infraspinatus tendon and then there is a place where these two tendons merge with each other and that is nothing but your conjoined tendon infraspinatus footprint is slightly larger as compared to your supraspinatus footprint and inferiorly posterior inferiorly is your pd spinal tendon now whenever you look at the rotator cup and you're evaluating rotator cup the supraspinatus tendon is best seen on a coronal image your sub scapularis and infraspinatus tendons are best seen on axial images so directed images you can evaluate all the tendons together so normally any tendon comprises of a footprint where it goes and attaches to the bone and there is a myotendinous junction where it where there is a junction between the tendon and the muscle and this is your tendon so but in case of supraspinatus tendon there is another zone which is important which is called as the critical zone now this critical zone is approximately one centimeter away from the footprint and this is important because in supraspinatus tendon this region is slightly hypovascular and because of the low vascularity it's more common to have degeneration and degenerative pairs in the critical zone of the supraspinatus tendon traumatic tears usually happen at the myotendinous junction besides whenever you get the gp avulsion then that will be a direct avulsion of the bone now the next thing is the bursa so you have a subacromial bursa which lies deep to the acromion process above the supraspinatus tendon and it can also extend this way downwards deep to the deltoid muscle so it is also known as subacromial sub deltoid bursa and the next two things that you need to be aware of is the sub scapularis recess and the sub coropoid bursa now sub coropoid bursa lies superficial to the sub scapularis muscle and it does not communicate with the joint it does not go deep to the sub scapularis muscle whereas the sub scapularis recess as you can see over here it will go deep to the sub scapularis muscle and it will also communicate with the joint effusion so this is how you can differentiate between the two the neurovascular bundles around the shoulder the two most important ones is the spinochleloid notch this is your glenoid this is the posterior aspect this is where the spine of the scapularis arises so this notch is nothing but the spinochleloid notch and it comprises of the supra scapular nerve now it is important because whenever there is a posterior labral tear a small glenoid cyst or a large glenoid sorry a ganglion cyst or a paralabral cyst or a large paralabral cyst it would extends into the spinochleloid notch it can abut or it can compress the supra scapular nerve in this region which would result into denervation edema so this is one important structure that you need to look at closely and the another thing is your quadrandular space which comprises of the axillary nerve any space of you find lesion in this region will again compress the axillary nerve and result into denervation changes now let us look at the tendons and the bursae on a coronal PD images so this is a porcupine process with a short head of bicep tendon the first structure anteriorly that you see is your sub scapularis tendon this is the sub scapularis muscle the myotendinous junction and this is now in this particular image you can actually pick up small delaminating tails in the sub scapularis tendon now as you go posteriorly you can see the bicep tendon and just next to the bicep tendon is your anterior suprasfinitis tendon now this is a common site for something called as rim-rent tails which are small arterial sided tails and it is often missed on a coronal image so make sure you correlate this particular region on a sagittal image as well as you go posteriorly you can see this is your suprasfinitis tendon so as I told you there is a footprint a critical zone and the myotendinous junction and then further you can see that there is a subacromial bursae in this region it is not visible unless it is distended with fluid then you can see that this is your infrasfinitis tendon and this is your quadrantular space infrasfinitis tendon t-rease minor tendon and the myotendinous junctions again infrasfinitis t-rease minor tendons and the myotendinous junctions so this is the posterior most section and now we look at them at the sagittal images so suprasinfra and the conjoined tendon where the two merge together this section is what we have seen in the diagrammatic representation so this is the multi-pinate sub-scat suprasinfra forming the conjoined and this this tiny black structure this is your t-rease minor tendon and this black structure is your biceps tendon so as you go posteriorly you can see that we will clearly make out the multi-pinate appearance of sub-scat here so there is one, two, three, four so there are multiple tendons in this region and for the posteriorly here you need to look at your muscle bulk or the muscle volume and you need to look for muscle fatty infiltration in this region so we have discussed this anatomy already and now on the axial images so suprasinfra is not well evaluated on an axial image when you go downwards you begin to see the sub-scatularis tendon which is arising from the lesser tuberosity this is your biceps tendon here and this is your sub-scatularis myotendinous junction similarly posteriorly you will see your infraspinatus tendon, infraspinatus myotendinous junction again over here you can appreciate the spinal clenoid notch then you have the t-rease minor tendon which is the lower most one this is your t-rease minor tendon t-rease minor is not much important because it is it usually does not tend so that is the least important of amongst all the rotator cuff tendons and the last thing that we're going to discuss in short is your ac joint or the acromioclavicular joint which is between the acromion process and the listerine the clavicle it is stabilized by the superior and inferior acromioclavicular ligaments and you have a coracoclavicular ligament between the coracod process and the clavicle so your ac ligaments or the acromioclavicular ligaments are better seen on coronal images so you can see if they run along the capsule and here also you can see so this is your clavicle this is your acromion process and this thickening is your inferior and this thickening is your superior acromioclavicular ligament similarly your coracoclavicular ligament you can see that this striated structure is your coracoclavicular ligament on a coronal image but it is better evaluated on a sagittal image but you can see this is the coracoid process the clavicle and then these are your coracoclavicular ligaments here so to sum up always have an approach to the ending scan make your own approach be comfortable with whatever you are doing and this is the checklist to look at the structures in different planes the important structures which are practically important so you in coronal from anterior to posterior you need to go through these structures sagittal from lateral to medial make sure you look at these structures and axial make sure you look at these structures from anterior to port and whenever in doubt please make sure that though one particular structure is seen better on one plane for related on other planes so that your hundred percent sure of your type process thank you