Ultrasonography of the Shoulder - SD

Introduction to Shoulder Ultrasonography

Hello, I'm Dr. Tony BofA from the Henry Ford Hospital in Detroit, Michigan, and I have the pleasure to talk to you about ultrasound of the shoulder and the more common pathologies that are seen during ultrasound exploration.

Welcome, hello and welcome to Sonar World. I have the pleasure of presenting ultrasonography of the shoulder today. The shoulder is the most requested examination in our institution. Out of the seven to 8,000 examinations per year, at least 60% are going to be that of the shoulder.

Indications for Shoulder Ultrasound

Here you see a list of the different indications why we perform shoulder ultrasound. You've got rotator cuff tears, calcified tendonitis of the cuff, subdeltoid, subacromial bursitis, biceps tendinosis, and tenosynovitis, glenohumeral effusion, impingement syndromes, and acromioclavicular joint diseases.

In addition, there are some masses that may be seen as suprascapular ganglion cyst, but for today's purposes, why don't we just shorten the list and concentrate mostly on rotator cuff tears, cuff tendinosis and contusion, calcified tendinosis of the rotator cuff and some of the impingement syndrome.

Normal Anatomy of the Rotator Cuff

Remember that for rotator cuff ultrasonography, we're going to be looking at them on orthogonal planes, both on long axis and short axis. Here you could see on your left hand screen the topographic placement of the transducer across the patient's right arm.

We're going to begin by taking a look at the supraspinatus in long axis. Try to remember that we do have to make a complete sweep for the entire rotator cuff complex, beginning with the subscapularis going into the supraspinatus into the infraspinatus. Finally, to the teres minor.

In between the subscapularis and the supraspinatus, you'll have the long head of the biceps tendon. For the normal supraspinatus and the long axis view, it has a contour that has the form of a paired beak in its appearance.

Here, you could see that in the long axis view that it begins with a bone acoustic landmark of the greater tuberosity. This is the ledge of the greater tuberosity. Then you have the downsloping part of the lateral deltoid shelf.

Another landmark that's going to be important is the anatomic neck that separates the ledge of the greater tuberosity from the convexity of the proximal humerus. Above the proximal humerus, you'll see this anechoic or hypoechoic line, which represents the hyaline cartilage particular surface of the proximal humerus.

Then you go in into the enthesis or insertion of the supraspinatus on the ledge of the greater tuberosity. Above that, now you get to see the typical echo signature of a tendon with its fibrillar pattern as the tendon inserts on the greater tuberosity.

More immediately now you'll see a relatively hypoechoic region, which represents the musculotendinous tendon junction of the supraspinatus. In the single slice above the tendon itself, you'll have the virtual space of the subacromial subdeltoid bursa, which itself is lined by a fat fascial layer that appears to be hyperechoic.

Then above the tendon you get to see the pennate structure of the deltoid muscle. Above that, you have the subcutaneous fat. And finally, the skin.

Notice that on the long axis view, everything is convex upwards, convexity of the humerus upwards. You have convexity of the tendon, then you have the convexity, upwards of the subacromial deltoid bursa, and of course convexity upward of the deltoid.

But in ultrasound, which is actually a tomographic modality, try to remember that after seeing something on profile. Now we have to see it on a second plane. In case in point, we're now going to see it from the long axis into the short axis.

Here you begin to see again the bone acoustic landmark of the humeral head, the hypoechoic stripe of the articular hyaline cartilage, and a little ghost on short axis of the long head of the biceps tendon.

As we proceed from the cuff interval, which is the space between the subscapularis and the supraspinatus we're in the long head of the biceps tendon goes and goes distally. You now begin to appreciate the rest of the rotator cuff. You see the anterior portion of the supraspinatus going to the posterior portion of the supraspinatus and well into the infraspinatus.

Many institutions will consider three and a half to four centimeters as the entire anterior posterior measurement of the supraspinatus infraspinatus complex.

Note again, that above the tendon that is seen as a bristle pattern on short axis view, you now approach the virtual space of the subacromial or subdeltoid bursa in the short axis view, which is a lot more commonly seen in the short axis view. Then in long axis view, you get to see the hypoechoic stripe representing the lumen of the subacromial subdeltoid bursa.

Above and below it, you have the hyperreflective lines representing the fat fascial planes above the subacromial subdeltoid bursa. Now, you appreciate the striated pattern in short axis view of the overlying deltoid, super adjacent to the muscle of the deltoid, you get to see the subcutaneous fat. And finally, the skin.

Notice, just like the long axis view, everything is convex upwards on the short axis view, convex upward of the proximal humeral head, convex upward of the tendon and short axis and convex upward of the deltoid muscle.

Clinical Evaluation and Imaging Modalities

In the evaluation of the patient. As, imagers, our referring physicians will help us greatly by giving us a great clinical history, and from there we get to decide as imagers which modality to use and the choices are radiographs. Ultrasound, MRI, computed tomography or CT. And finally arthrograms.

Usually arthrograms are in combination with MRI and or CT history is very important and so most of us will usually might have a little bit more extensive interview of the patient.

One of the advantages of musculoskeletal ultrasound is now you are with a patient and so therefore you can extend the interview and get to know a little bit more about the history of the patient.

It is very important, that you have a baseline conventional radiograph of, the patients as far as their symptoms are concerning. It is important because as you'll notice in this case, for example, that there is irregularity of the greater tuberosity actually insinuating into the lateral portion of the acromion head.

And this cortical irregularity now is the basis of why we would've ordered an ultrasound. Case in point, it is, well known from an Hollander and Woolwine that if there is cortical irregularity of the greater tuberosity, there's three quarters chance, that there's going to be rotator cuff disease.

Likewise, if the cortex was pristine according to John Jacobson from the University of Michigan, then there's only 10% chance that you're going to find an abnormal rotator cuff.

So from here, therefore you could quickly see that an ultrasound, which is excellent, for resolution, since it's a tomographic modality, you get the sonographic confirmation of the cortical irregularity affecting the greater tuberosity.

Super adjacent to that, now you begin to appreciate a hypoechoic defect sharply marginated from the articular side to the bursal aspect, compatible with a full thickness tear on long axis and on short axis, you could see that this hypoechoic defect again interrupts the junction between the anterior supraspinatus and the infraspinatus, compatible with a full thickness tear.

Adjacent to this hypoechoic defect. On the short axis view, you see the moderate cortical irregularity already seen nicely, radiographically on the baseline or entry level study. This is known as the naked tuberosity sign and as we'll talk about it later, is a secondary criteria in order to diagnose rotator cuff tears, especially for full thickness tears.

The reason for baseline radiograph, sometimes is maybe not appreciated as much, especially since if you have a patient, like this who comes in or in the entry level, radiographs were interpreted as negative for fracture. Well, weeks later, the patient of course comes to you because of chronic shoulder pain and what we see here first on the long axis view is as you approach the tip of the paired beak contour of the supraspinatus, you see a high level echo, but immediately underneath that you have an interruption of the bony acoustic landmark of the anatomic neck.

And as you direct your sight towards the lateral deltoid shelf, you notice that again, the same interruption is seen. This is on the long axis view for confirmation. Now you do the short axis view and as we approach the greater tuberosity, of course the volume of, the rotator cuff thins out because that is the tip of the paired beak 'cause you can appreciate on short axis view and on short axis view, the same cortical disruption or interruption are noted both underneath the supraspinatus headed towards the infraspinatus.

I do not have the baseline radiographs of this individual, but of course, as you can anticipate on the follow-up radiograph, now you begin to maybe at least see a hint of a fracture of the greater tuberosity. But with the ultrasound now at hand, and you can ask a more tangential or a better profile view of the greater tuberosity.

And now you can see first on the frontal view and a tangential view, clearly the undisplaced greater tuberosity fracture that was already picked up on ultrasound.

Full Thickness Rotator Cuff Tears

For rotator cuff tears. Let's divide it into full thickness and partial thickness tears. For full thickness tears, we can use the major criteria and the minor criteria.

For the major criteria. We're going to use the list of Bill Middleton from Mallinckrodt, and his list includes an absent cuff, cuff atrophy, echopoor defect and focal hyperechoic defect.

Major Criteria for Full Thickness Tears

For the absent cuff. What it simply means is that, clearly you cannot visualize, the volume of the tendon that you anticipated on the long axis view. You could note that you are missing the paired beak, voluminous thickness of the tendon. Instead, you have the pennate structure of the deltoid muscle just resting directly on the surface of the humerus.

For the novice in musculoskeletal ultrasound, this might be difficult, but you are missing one structure because you see the bone acoustical landmark of the proximal humerus and greater tuberosity, albeit as you can appreciate, it's irregular and then you're anticipating a fibrillar pattern for a tendon and it's not there. Instead, you get the pennate structure of a muscle representing the deltoid. Finally the fat and then the skin on the short axis.

If you likewise, you're anticipating a curvilinear bristle pattern of a tendon. Instead, you have the bone acoustic landmark of the irregular humerus and greater tuberosity and lying directly on it is a striated pattern of the deltoid muscle and short axis.

So do we still need an x-ray? Why not? In order to convince people that indeed there is an absent cuff. Here you could see that there is virtually no space for a rotator cuff to exist between the inferior cortical border of the acromion and that of the proximal humerus in greater tuberosity in these individuals.

Therefore, the presence of a subacromial spur, the decrease of the subacromial space and the glenohumeral osteoarthrosis will be equivalent to rotator cuff atrophy. So the non visualization or the absence of a cuff means that there is a full thickness tear in the shoulder.

The second criteria used by Dr. Middleton is cuff atrophy, actually, probably a more difficult word to use nowadays, but it is in the literature and we'll stick to it for tendon atrophy. First, let's rehearse one more time that the paired beak appearance of, the supraspinatus in the long axis view shows that it has a convexity upward contour.

It's usually pointed out well by Dr. Tom Winter and for tendon atrophy, what happens now is you appreciate visually that the more distal portion of the tendon may be thinned out or atrophic case in point here, for example, as you go from the medial to the lateral aspect of the supraspinatus, it now becomes a little pencil thin and into a teardrop sign over the lateral deltoid shelf.

Sub adjacent to to this thin tendon. You see the cortical irregularity that will be equivalent to the naked tuberosity sign on long axis view. What happens here is actually the stump of the tendon is going to be at the level of the anatomic neck, giving you like a stage two type of retraction.

However, because granulation tissue scar fibrosis is equally hyperechoic or at least isoechoic to the normal tendon, it seems to be that it's just a simple thinning out of the tendon. In addition, of course, the synovia within the subacromial subdeltoid bursa, along with its proliferation, will have the same echogenicity and making the entire tendon appear to be tapering laterally.

In an actuality this is just scar tissue and that the stump is already retracted over the articular surface of the humerus. Here again, the arrows completely tell you that the sign of tendon atrophy is an excellent, way. In one of the, major criteria to diagnose a full thickness tear of a tendon.

The most common criteria that you'll be coming across would be the hypoechoic defect. The more frequently seen hypoechoic tendon defect, as you could see, will be echolucent. In case in point here, you could see it just over the medial footprint of the supraspinatus.

In the long axis view, it will have a sharply marginated border, and more often than not, you should be able to see some early cortical irregularity, of the adjacent greater tuberosity. On short axis view, the same thing look for the hypoechoic tendon defect, most often than not, accompanied by a sharply marginated border.

In this case, you can see that the defect is in the anterior portion of the supraspinatus. The rarest of all criteria is going to be the focal hyperechoic defect. One of the few cases that I possess is this one here helped, actually gathered at my hospital by a visiting fellow Dr. Sum Lee, wherein you get to see that there is a strand of hyperechogenicity smack in the middle of, the supraspinatus.

In these long axis view, you may already suspect, that the volume has increased and that the echogenicity has decreased in this individual, again, giving you superimposed tendinosis or edema if you wish. And in the short axis view, of course, this may appear as a more punctate type of defect, which should be confused easily with a calcified lesion.

Of course, the hyperechogenicity may be blood, or it could be maybe the nitrogen gas, from the joint itself. Sometimes when you have a sharp tear, all the layers and direction of the fibers may fall uniformly in a certain direction, accentuating it as a hyperechogenic defect.

And for confirmation, we needed, MRI in this case we're in after the injection of gadolinium contrast. You could see that on this fluid sensitive sequence on coronal plane that the fluid in the glenohumeral joint transits, from this articulation and goes across the entire tendon, much in the oblique direction that you can appreciate on ultrasound and into the subacromial subdeltoid bursa, along with a teardrop collection of fluid along the lateral deltoid shelf confirmation that indeed this is a full thickness tear that connects from the articular surface to the bursal surface of this defect compatible with a rare hyperechoic focal defect in this individual.

Minor Criteria for Full Thickness Tears

Let's now move on from the four major criteria into the minor criteria that we still would help in the diagnosis for full thickness tears in rotator cuff tendons for minor criteria. Let's begin by taking a look at abnormal fluid.

Go into the already well known naked tuberosity or how the way we started it when we talked about the baseline radiographs and then go into the leak sensitive or specific all which is gonna be cartilage interface sign. And finally, the very convincing deltoid herniation sign as a part of this list for the abnormal fluid collection.

The most specific is effusion in the subacromial subdeltoid bursa, as you can see here, highlighted in red. Let's begin with that and then jump into the long head of the biceps tendon. Second on the list because it's the first structure that you're going to see when you look at the anterior region of the shoulder.

And then another, very specific, collection of fluid would be in the glenohumeral joint. Finally, and a little bit more outstanding would be any fluid that is collecting in the acromioclavicular joint.

Let's begin by looking at the subacromial subdeltoid effusion, and there will be a couple of types that you'll come across First as the chronicity and probably the more common of the two that you'll be appreciating. You'll get to see the proliferation of the synovia within the subacromial subdeltoid bursa in the ballooning and distension of the bursa or the bursa itself.

Note that there is a full thickness there. As you could see the hypoechoic interruption of, the long axis view of the supraspinatus and fluid transits from the articular surface into the bursal surface of this individual.

The lesser common one is when you have an acute tear wherein now you could see fluid transiting from the articular surface actually originating from the glenohumeral joint, not shown here. And as it goes through the articular level into the bursal level, it now balloons and distends the entire subacromial subdeltoid bursa including a teardrop sign along the lateral deltoid shelf.

The long head of the biceps tendon is the first structure that many of us would see, and the short axis view where we start, might appear as a bullseye lesion as you could, appreciate. In here, here you see the bicipital groove, the lesser tuberosity, and on the lateral aspect, the greater tuberosity smack in the middle.

On short axis view, you see the bristle pattern of a tendon surrounded by fluid, markedly distending its sheath compatible with a distended bicipital tendon sheath in short axis, as you well know that in ultrasound we have to see it on orthogonal plane, so therefore on long axis view, now you get to appreciate the fibrillar pattern of the long head of the biceps tendon.

But again, one more time surrounding fluid around the tendon sheath. Dr. Bill Middleton, states that, if you see this, and again, I told you that this is one of the first structures you're going to see when you explore the shoulder, then there is a 50 to 55% chance that you're going to be seeing rotator cuff disease in addition to the fluid around the tendon.

Note to that, there is, some hypoechogenicity of the biceps tendon itself. So there is accompanying or concurrent, tendinosis of these, this particular segment of the tendon.

The glenohumeral joint is also important as you can well note that once you get abnormal fluid collection is in this case wherein you have the bony glenoid, the bony humerus and absent glenoid labrum. Here you could see the collection of fluid descending the capsule markedly and therefore this effusive joint, tell you that chances are you're going to have rotator cuff disease.

While it may be difficult initially to appreciate the effusion in this joint, when you do compare it to a normal joint wherein you see the bony glenoid humerus labrum, so you've got the glenohumeral joint labrum and the fibrillary pattern of the infraspinatus note that the capsule itself is imperceptible or at least, collapsed in comparison to the abnormal side.

What's important here now is if you were to combine two or three of the abnormal effusive findings, then the sensitivity and specificity of rotator cuff tears increases case in point taken alone. The long head of the biceps tendon, for example, will tell you that there's only a 55% chance that there's gonna be rotator cuff disease, but if you're to combine that with fluid, let's say in the glenohumeral joint, then you increase that accuracy to about 70 to 80%.

But the minute you see fluid in both the subacromial subdeltoid bursa and the glenohumeral joint, then you're way above 85% sensitivity specificity for abnormal rotator cuff.

Let's finish, with the minor criteria, at least as far as abnormal fluid collection is concerned. By taking a peek at the acromioclavicular joint, the probe is placed on the vertex, which is the highest point in any structure off the shoulder, across the acromion and going into the clavicle. And then we will identify the joint line.

Here you could see the bone acoustic landmark of the right acromion as you cross into the medial aspect of the right clavicle. And in between the two you'll see the joint line plus a minimally distended and average distension of the capsule.

Note the, proximity of the acromioclavicular joint to the rest of the rotator cuff and that of the subacromial subdeltoid bursa. What happens over time in individuals who have rotator cuff tears is that the underside of the capsule of the acromioclavicular joint itself erodes.

So from there you'll see fluid coming across through the rotator cuff and pumping itself into the acromioclavicular joint from the inferior or under surface of this joint. Here, not only do you see a distension of the joint and its capsule, but also some intrinsic debris within the effusion of this individual.

This is known as the geyser sign. So when you have fluid pumping out and jumping out from the acromioclavicular joint, then it looks like old faithful and Yellowstone parked as a geyser skyward. And notice the height of, the fluid.

The geyser sign probably is better expected and seen. When you do an arthrogram of a shoulder with a full thickness tear, you know that in an intact rotator cuff, the contrast should only stay in the glenohumeral joint and around the tendon sheath and part of the recesses.

But here you can see that the contrast has escaped, from not only the joint but across the rotator cuff into the lateral deltoid shelf or a teardrop sign. And as it creeps into the subacromial bursa, it now jets skyward through the acromioclavicular joint confirmation of the geyser sign.

This now of course, will tell you that this is abnormal, and while it's largely a clinical sign on ultrasound, the sonographic geyser sign one more time is seen as all this fluid gushing upward and superiorly away from the joint line acromioclavicular joint.

And it's not uncommon that it's going to be accompanied by some bursa de novo or brand spanking new bursa. For comparison, jump to the usually more asymptomatic side, although there's some distention on the left shoulder, you could really note the difference and the height of the fluid shooting out from the abnormal right acromioclavicular joint.

So this would represent, a unilateral sonographic geyser sign right side, as in this case, and it'll be equivalent clinically to a geyser sign as seen nicely on this patient.

Let's move on from, the, minor criteria of effusive, findings in the shoulder into the naked tuberosity sign. We already have rehearsed it, quite nicely and so the cortical irregularity of course is a signal that there may be rotator cuff disease.

Let's jump on into cartilage interface sign. What happens here is that there's no longer any impedance of, the sound waves that it goes through the usually liquid filled gap of the tear. In the short axis view, notice that there is a hypoechoic tendon defect, and as the sound accelerates, through this hematoma or fluid, the next interface is going to hit as the surface of the articular hyaline cartilage.

Below it, the next hyperechoic line is the subchondral plate on short axis view. On the long axis view, probably a little bit more difficult to see, but still present. You'll get to appreciate maybe immediately the hypoechoic tendon defect, but adjacent to that one more time, you see the cartilage interface sign and the last hyperechoic line is the subchondral plate of the humerus for a positive cartilage interface sign.

This is the at least, specific of all and may be seen in people who have edematous tendon, super adjacent to the articular surface. However, it's still very helpful because if you can combine one or two or more of the minor criteria sign, then you're still on your way to diagnose a full thickness tear.

The last is going to be deltoid herniation sign. And what we see here usually is on short axis view, the volume and contour of, the rotator cuff is described as a well inflated car tire, so therefore you'll have convexity of the bone acoustic landmark of humerus, convexity of the tendon itself looking at well inflated car tire, and then also the convexity of the deltoid muscle.

Here gets in point, you see planing out or flattening or even collapse of the tendon already appearing as a flat tire. The deltoid herniation sign is more specific and better seen on short axis view, and when you go into the long axis view, again, you'll notice that the convexity upward of the expected rotator cuff contour is reversed.

You see the concavity and later on, as this scars down, this may now evolve into the atrophy sign, which is a major criteria of full thickness tears. So in two views now confirmation of the deltoid herniation sign, again helping us with the criteria of a full thickness tear.

It is not until you begin to look at, rotator cuffs and dynamic imaging that you can appreciate the full thickness tear. A case I share with, Dr. Pera from Oslo, Norway here on the long axis view, you'll note that when we are on the anterior portion of the supraspinatus, it may look intact with the convexity upward of the tendon itself and the nice fibrillar pattern, but as we sweep from anterior to posterior, you'll notice all of a sudden that there is a hypoechoic tendon defect over the greater tuberosity of the proximal humerus.

And you'll notice that as we scan and make a sweep back and forth, that this defect connects from the articular surface all the way to the bursal aspect of the tendon. Again, its corollary is going to be in the short axis view. You'll appreciate the fact that as we scan from the acromion to the greater tuberosity level, that you may maintain some of the tendon volume later on as you approach the tendon defect.

Not only will you appreciate the hypoechoic sharply marginated tendon defect of the posterior supraspinatus, but also that there is a deltoid herniation sign reversing the usual convexity of the tendon itself. Note that over here you see the bristle pattern in short axis view of the long head of the biceps tendon and that this would be the anterior segment going into the posterior segment of the supraspinatus.

Therefore, dynamic imaging seen a loop and video clips are essential in order to clearly appreciate what's going on with this individuals.

Partial Thickness Rotator Cuff Tears

Let's move on from full thickness tears into partial thickness tears. There are four levels that, we'll be taking a look at. And let's begin by taking a look at the different surface superiorly. We can begin from the bursal surface and then we go into the intrasubstance or inter tendinous area and finally into the articular surface.

One of the more common and incipient, partial thickness tears that you'll be visualizing would be the rim rent, which is actually a small or early form of articular surface tears. Well, let's include it as part of the list 'cause it's, pretty well common.

What we're going to be seeing, this probably is my gold standard as far as I'm concerned when it comes to the long axis view of a rotator cuff wherein you see the fibrillar pattern of the supraspinatus inserting on the greater tuberosity with a small tubercle for the glenohumeral joint of the greater tuberosity.

As you scoot on medially, you'll see the anatomic neck and finally, the convexity of the proximal humerus, uninterrupted fibrillar pattern. As you can appreciate here, and as we move from the hyaline articular surface of the proximal humerus or the undersurface, better known as the undersurface of the supraspinatus, we now go into the convexity upward of the bursal level or surface of the rotator cuff.

Above that, you get to see the pennate structure of the deltoid as a muscle in a long axis view. This is courtesy of, Dr. Javier de la Fuente from San Sebastian's Pain. As you can appreciate, the name of his clinic here, the different levels where partial thickness tears will occur will be, let's begin again from the superior portion would be the bursal aspect.

From there, we could jump into the intra tendinous or intra substance portions, wherein again, it is a second type of partial thickness tears. Anytime that there's an interruption of the rotator cuff that touches the hyaline cartilage, al proximal humerus than you have an articular sided, partial thickness tear, like I told you, the, earliest sign and evolving partial thickness tear on the articular surface, usually at the reflection, the reflection of the rotator cuff is right over the anatomic neck as it, invests again on itself and this would be a site of the rim rent.

Equally important and more commonly probably seen and appreciated in MRI in comparison to the underutilized ultrasound examination of the shoulder is going to be the footprint tear of the rotator cuff. The footprint of the supraspinatus invests itself or steps on the greater tuberosity of, the proximal humerus or at least the enthesis or insertion of this area.

So the location of the footprint tear is near a but is not articular sided strictly at the anchor of the supraspinatus and or the other tendons, and therefore would be intrasubstance or intra tendinous.

Let's, take a look at some examples for bursal surface. Probably immediately more appreciated would be on the short axis view. On the short axis view. You'll notice as you look at the convex, the upward of the bursal surface that there is an interruption or hypoechoic tendon defect affecting the bursal aspect as you go down into the intrasubstance portions.

But as you glance over to the long axis view, you'll notice that this one approach is more the musculotendinous junction. I think most of the bursal aspect here are better appreciated on short axis view, but you should always try to catch them and confirm them on the orthogonal long axis view.

Dr. Kuda, who was a, a fellow for Dr Near claims that a fifth of the partial thickness tears that you'll be seeing in the shoulder will be the bursal aspect type.

The most common type of tear that you should be seeing is going to be the intrasubstance type of partial thickness tears. These will occur as sharply marginated hypoechoic tendon defect, again, leaving the bursal surface alone and definitely not extending into the articular surface near the hyaline cartilage on long axis view.

As you see this defect on the mid portion of, the supraspinatus on long axis view and on short axis view here, as you could expect, the anterior posterior portion of the supraspinatus, again, this hypoechoic sharply marginated tendon defect. Again, not approaching and leaving the bursal aspect alone and also not invading the hyaline cartilage.

Dr. Kuda thinks over half of the cases of partial thickness tear should be of the intra tendinous type.

I bet you that most of you probably think that this is going to be the more common partial thickness tear because it affects the articular surface. The articular sided partial thickness tear will appear as a hypoechoic tendon defect, sometimes maybe of mixed echogenicity, but definitely it lands on the hyaline cartilage over the anatomic neck of, the rotator cuff in this long axis view on the short axis view.

Likewise, you'll see that definitely it already touches the hyaline cartilage, without the cartilage interface sign in this case, but again, sharply marginated hypoechoic tendon defect sitting on the hyaline cartilage of the proximal humerus. A fourth of, the patients will possess this one.

The rim rent is the earliest, of all partial thickness tears and has already been described, but Dr. Codman, same physician who described codman's tumor, which is a chondroblastoma or the codman's triangle for osteosarcoma and or osteomyelitis rents, like to occur, the reflection of the under surface of the rotator cuff.

As you can see here on the long axis view, it'll appear to be a smaller hypoechoic tendon defect, sometimes appearing as a bullseye lesion because of its more mixed echogenicity. Note that immediately sub adjacent to the rim rent would be a moderate to deep cortical pit or cortical irregularity.

On the short axis view, the bullseye lesion is a little bit more obvious as you can appreciate it. And one more time, the sub adjacent cortical pit of rim rent In our cadaver studies, like we told you that these rim rents are on the under surface, usually in the critical zone, which is the first square centimeter immediately adjacent to the long head of the biceps tendon in here.

You could appreciate again the fraying on the underside of the cadaver studies that we do in order to study and get to know the rim rents better in our institution.

For full thickness tears, if you'll allow me, I'll just combine sensitivity and specificity together to have an accuracy. So we do have an accuracy approaching that of 98%. We do trickle down a bit when we look at partial thickness tears in our institution where in our accuracy drops down to 94%.

However, now you begin to appreciate the fact that indeed rotator cuff tears are accurately diagnosed with ultrasonography.

Subscapularis Tears

Most of the rotator cuff tears I've been talking about of course involve the supraspinatus and some of them delaminating towards the infraspinatus. But a more fascinating one now is when you look at the subscapularis, most of these will occur in younger individuals and they will involve trauma.

Case in point here, you could see the snowboarding accident. This drawing was courtesy of Miss Elise Van Hvi who's now in medical school herself, and when these occurs, and this is what you're going to be expecting when you take a look at it on arthroscopy as you go posteriorly approaching it, you are missing the pearl white fibrillar pattern of the subscapularis on ultrasound.

First that we're going to be looking at the left shoulder and you're expecting a musculotendinous junction and fibrillar pattern of the long axis view of the subscapularis in between the bone acoustic landmark of the coracoid and that of the lesser tuberosity.

Instead, you begin to see a hypoechoic sharply marginated tendon defect delaminating medially and laterally underneath the deltoid muscle for a left right comparison. Now, when you look at the right subscapularis, notice the bone acoustic landmark of the coracoid and that of the humerus and the intact fibrillar pattern that you can appreciate of the subscapularis.

Obviously, the of the findings will give you a great hint what's happening to these subscapularis, but it's not until you proceed a bit more lateral that you appreciate that the delaminated acute tear, full thickness tear of the subscapularis as it approaches the long head of the biceps tendon and the bicipital groove.

Often for confirmation, you may need MRIs, this case important same patient wherein again, you have the long head of the biceps tendon and then the stump of the subscapularis and absent of the signal void tendon that was expected at the level of the coracoid.

Tendinosis and Edema

In this actual view of the shoulder left shoulder, Aside from full thickness tears and partial thickness tears, of the rotator cuff, it's not uncommon to see some edematous enlargement of the tendons. First, let's again rehearse with the normal asymptomatic side in some of these individuals, and when you go to the more symptomatic painful shoulder, this is what you'll see.

Sure continued upward, preservation of the convexity of the tendon, but look at the change in volume in this individual in comparison to the normal rotator cuff. So those are three things that we try to look for. You try to look for size contour, and the third and last, of course, is going to be the echogenicity.

You see the fibrillar hyperechoic changes of a normal or echo signature actually rather than changes in the supraspinatus, and obviously you could see the difference. In addition, the normal side maintains its pristine bone acoustic landmark in comparison to incipient changes affecting already the shoulder that is undergoing tendinosis.

With doppler, you have a positive doppler angiography where you could appreciate the neovascularity occurring in an individual with focal tendinosis at the lateral aspect or footprint area of the supraspinatus in long axis in short axis. Again, same confirmation of the doppler positivity, perifocal or across the hypoechoic tendon defect itself for tendinosis and since it's a spectrum of disease might also be already an evolving intrasubstance partial thickness tear.

Calcific Tendinosis

After that, we've seen tears and tendinosis. Let's now go to a little bit more complex type of tendinosis. When you look at calcifications of the shoulder on the baseline or correlative radiographs of the shoulder, you'll see this radio opacity in case in point sitting over the ledge of the greater tuberosity on ultrasound.

Of course, you can anticipate that you're going to be seeing a high level echo with posterior acoustic shadowing confirmation of the same calcification that we've seen in the supraspinatus, interrupting the bristle pattern of the short axis view of this tendon and approaching that of the subacromial subdeltoid bursa.

Most of this calcifications are of the concrete type, although you could have those which may be more like toothpaste or even milk of calcium. But here, case in point, for example, we're seeing the same, video clip wherein the abnormal high level echo in the intrasubstance portion of the rotator cuff is causing some impingement between the greater tuberosity and under surface of the acromion.

Here on a more static view, you have the acromion, the abnormal high level echo of the calcification and the obstructed abduction course of the greater tuberosity. So if you take a peek at that, that glitch is responsible for the subacromial impingement in this individual.

Simply today. An ultrasound, once we have confirmed on radiographs the opacity that you could see at the very angle of the greater tuberosity on long axis view. Of course, this is a standard rendition of an ultrasound where you get the medial aspect, lateral aspect.

On the long axis view, you'll see this high level echo without too much posterior acoustic shadowing because of the density of this calcification immediately on short axis view, you confirm the same echogenic lesion with minimal posterior acoustic shadowing for its location.

Nowadays, percutaneous aspirations of this calcifications are easily performed under ultrasound guidance. Here you could see the shaft of the needle as it approaches the abnormal calcification of the tendon.

Once we impale the bevel and tip of the needle into this calcification, we're going to go distend with some saline and the pressure itself, the intrasubstance pressure itself will again cause the backflow of the calcifications into the needle itself, and this should implode and therefore you could percutaneously aspirate majority of the calcific tendinosis excellent use of musculoskeletal ultrasound in percutaneous intervention.

Impingement Syndromes

Let's now, finish our discussion about shoulder pathology and under ultrasound by taking a look at, second to the last or penultimate about subacromial impingement. Remember the calcifications that we showed earlier that cause obstruction or the more common cause for obstruction usually is tendinosis or subacromial subdeltoid bursitis.

Remember that when the shoulder elevates or abducts that not only must the greater tuberosity clear the under surface of the subacromial or the acromial process, but also the tendon itself. And as you can see here, the subacromial subdeltoid bursa.

Let's look at a normal abduction of a shoulder. We're gonna use a left shoulder here where you see the bone acoustic landmark of the acromion and that of the greater tuberosity and of course the paired beak appearance of the tendon. Notice that without friction and without effort that the shoulder can abduct nicely underneath the acromion, the abnormal type of shoulder.

Instead. Now you could see that underneath the acromion that the hypoechoic fibrillar pattern of this rotator cuff cannot now go underneath or tuck itself underneath. Notice too that you begin to have not only a thickening, but also a ballooning or cording type of subacromial subdeltoid bursa.

Glenohumeral effusion on radiographs would be probably a bit more difficult to appreciate, but on MRI with fluid sensitive sequence at the level of the coracoid and subscapularis, you'll notice all the fluid in the posterior area note, that the capsule may invest itself at the apex of the glenoid labrum or behind it.

But the whole point here is that you confirm that there is a distended capsule and of course the fluid on MRI at the intraarticular portion on ultrasound, as you perform a ball and socket maneuver, when you ask the patient to rotate his or her hand out, you'll notice the glenohumeral joint, and when you do that, therefore the capsule will slide backwards and you'll see some physiologic or minimally increased fluid in this individual.

This is the maneuver when you ask the patient to swing their hand out. Now, patients don't know about external rotation, so you say, can you please swing your hand out? And therefore now you can begin to appreciate that the infraspinatus as it externally rotates distends the capsule and accentuating the glenohumeral joint.

When you take a look at an abnormal glenohumeral joint, much like we already initially showed on the MRI, you'll see the distension and ballooning out of the posterior capsule, even separating the glenohumeral joint a little bit more on external rotation or as the patient swings their hand out.

The normal side, again, almost imperceptible distention of the capsule. This is important because as this labrum degenerates, you begin to cause some posterior glenohumeral labral tears, and when that happens initially, if on a neutral or non-stressed non rotation view, you may begin to think that the labrum may be intact, but already collecting around it are some hypoechoic changes, maybe even a hypoechoic cleft across it because when they externally rotate their arm, now you see that the disintegrating fragmented glenoid labrum is more obvious and the fluid collection around it is compatible with a labral or paralabral cyst.

The posterior impingement, therefore, as the humerus impales into the glenoid labrum, now begins to fray the labrum for a posterior impingement. And naturally, most of us probably may need MRI to take a look at it.

And on this fat saturated coronal image, you'll notice the glenohumeral joint and of course the signal void of the labrum, but around it, a cystic collection and lobulated, collection of abnormal cystic lesions compatible paralabral cyst. But we already knew that from our ultrasound image where you have the glenohumeral joint, an indistinct hyperechoic labrum, and of course the collection of the cyst compatible with a suprascapular ganglion.

Acromioclavicular Joint Pathology

Let's finish, by taking a quick look at the Acromioclavicular joint. Remember that immediately a left right comparison, left right comparison can show you that the unaffected left side, you have almost a plain out view of the dorsal capsule, while much more distended right side with Doppler positivity on both right and left side, you'll notice that of course this is the affected type for a case of Acromioclavicular Osteoarthrosis.

A case from Dr. Kho Cho from D**o CHOA that we share here will show you that on ultrasound in comparison to the unaffected left side, that the right side, the acromioclavicular joint is not only distracted, but that the recess, which is eccentric towards the clavicular side in comparison to the normal recess on the unaffected left side will show that on the right side there's some fluid collection.

Of course, inflammation, trauma, sepsis, synovitis, even tuberculosis may be considered, but it's not until you do an MRI that maybe that's confirmation from the T1 morphologic sequence to the fluid sensitive T2 sequence that you'll see all these changes.

A little bit more frightening, of course, after aspiration ultrasound guided unless you have an open MRI Mag, this was just a simple case of post-traumatic hemarthrosis off this joint.

Probably one of the more common and exciting ones that we see is the eccentric changes or subchondral cystic changes of the distal clavicle in such an individual that may not be affecting the subarticular portion of the acromial process on ultrasound, the same thing can be appreciated that if you look at the acromion in the subchondral plate, you'll notice that it's still pristine.

And here on the distal clavicular portion, the subarticular cystic changes already confirmed radiographically, but again, seen on ultrasound clearly shows that this is the affected side. But in addition, you also see that there is abnormal fluid collection, and so therefore this effusive joint trickles out towards eccentrically towards the clavicle for a left right comparison, again, the unaffected left side shows pristine subarticular area, non distended capsule in comparison to the affected side.

These are the long axis views of the acromioclavicular joint, and if you take a look at the affected side, you'll have internal debris and irregularity on short axis view in comparison to the unaffected left side, this is a great case of post-traumatic osteolysis in this individual.

Conclusion

In conclusion, Musculoskeletal ultrasound is very sensitive and accurate for full thickness tears. You drop a little on partial thickness tears naturally after tendons, effusion, synovitis is easily detected with ultrasound.

Again, the most specific at all of all for, especially for full thickness tears, is if you do have fluid collection in the subacromial subdeltoid bursa tendinosis or maybe even incipient partial thickness tears are readily seen because of the changes in contour size and echogenicity calcific tendinosis even is easier to detect when you see the high level echoes within the tendon substance.

Last but not least, so we got to show you some subacromial impingement and that of a posterior impingement, and these cases were in, not only are the tendons affected, but also the subacromial subdeltoid bursa. In addition, the posterior impingement may lead into the evolution of suprascapular ganglion that may impinge on the suprascapular nerve groove and on the neurovascular bundles, which may result in the atrophy of the infraspinatus muscle.

Thank you very much for your attention.