Shoulder Ultrasound Anatomy and Technique - SD

Introduction

Hi, I'm Dr. Nand Raul. I'm from Tama Jefferson University. I'm the program director for the ultrasound program, and I'm the associate professor there.

Today we'll talk about the ultrasound of the shoulder and look at the anatomy and the scanning techniques. Today we'll look at the shoulder ultrasound anatomy and the techniques. This part deals with mainly the anatomy and the normal anatomy and the scanning techniques to be performed when you do the shoulder ultrasound.

Shoulder Anatomy Overview

If you look at the shoulder itself, one of the things you should familiarize yourself is looking at the bony prominences on the shoulder because that's how you would be able to look at the shoulder joint and scan the anatomy. You want to look at the greater tuberosity, the lesser tuberosity, the head of the humerus, the clavicle, the corticoid process. So when you look at the muscle tendon and the anatomy are able to orient yourself with these bony prominences.

If you look at the shoulder ultrasound, look at the shoulder joint, it's very shallow and part of the reason it's shallow is because the shoulder joint needs to have a lot of movements and it needs to be very flexible. Of course, it also makes it very unstable and are prone to injuries, as opposed to that. If you look at the hip joint, it's very deep. So what that does is it gives you a very stable joint, but obviously you can make a lot of movements that you would do with the shoulder.

Here are some of the shoulder movement that you can do with ultrasound.

Scanning Techniques

When you look at ultrasound of the shoulder, one of the things to remember is you want a very high frequency transducer. Most of the transducers tend to be 10 to 15. Most of the newer transducers tend to be close to 15 megahertz. Also you want the capacity to downshift in frequency, which means the 15 megahertz gives you a better image quality, but a lower frequency like a 12 or a 10 gives you a deeper penetration for the shoulder joint.

You can scan ideally having a patient sitting on a stool. What that does is it gives you an ability to look at the anterior and the posterior shoulder, and you can look at both of them in a similar position and have the patient turn around. It's never a bad idea to look at both shoulders, and part of the reason for that is because you can always compare the abnormal shoulder with a normal shoulder on the opposite side, especially if you're new to scanning shoulder. That's a good way of making sure that you know what anatomy you're looking at.

As far as imaging, the orientation of the transducers, you basically image like you would do for the x-ray.

Rotator Cuff and Key Structures

Coming to the shoulder ultrasound itself, what you're looking for now is when you're looking for the shoulder ultrasound, you're looking for the rotator cuff and you're looking at the couple of important structures. The rotator cuff consists of basically four different tendons, the subs, capillary tendon, the supraspinatus, the infraspinatus, and the t mine. There are two other structures you should look for when you're looking at the shoulder ultrasound or the shoulder joint, and that's namely the biceps tendon and the deltoid muscle.

So if you look at this lateral anatomy of the shoulder joint, what you see up there is there's this supraspinatus tendon. There's the infraspinatus tice minor and the subscapular. And what that does is it forms a cuff around the joint or the shoulder joint. You also see the deltoid muscle on top.

The other thing you should know is when you're looking at the shoulder joint is to know the anatomy of the tendon and the muscle itself. So it's not a bad idea to orient yourself with the origin and insertion of the muscle and the tendon. So if you look at this picture there, there's this scapular with the supraspinatus fossa and the infraspinatus fossa. The supraspinatus fossa gives rice to the supraspinatus muscle and the infraspinatus to the infraspinatus muscle.

Also you should know where these tendons insert because in order to elicit the movement, you need to know where the shoulder comes from or the shoulder tend anatomy and the shoulder muscle and tendons come from. What you also need to look for is the insertion of these tendons, because that's where you will find some other pathologies, especially a little bit before the insertion. You might find that there's a tear, which are more common close to the insertion.

Biceps Tendon

So let's first look at the biceps tendon. When you're looking at the biceps tendon, you can look at the long and the short head of the biceps, even though it's not visualized routinely because many of the joint anatomy is within the joint itself.

So you start looking at the shoulder anatomy and transverse for the biceps tendon. This is the anatomy that shows you the biceps tendon and the movement that the biceps tendon has. If you're looking at in transverse, what you want to do is there's the biceps tendon with the shoulder in a flex position, neutral position, and this is where you have the probe placed in the transverse position. What that does, it gives you a biceps tendon in transverse, and this is the bicipital groove. So what you're looking for is the biceps tendon within the groove itself. And then when you scan transverse at that tendon, you should be able to see the tendon and the bal groove. So there, there's the tendon, which is oval and shaped, and there's the tendon resting in the bal groove.

Again, there's the tendon anatomy with the biceps tendon and the transfer tendon section taken at the level of the biceps tendon. And over here, what you can see is basically the oval shaped biceps tendon within the groove.

Once you finish that, you want to look at the biceps tendon in long axis. So you would again do the similar anatomy scan, scan the biceps in long axis. So there's the long axis view, and by looking at the long axis view, what you get up here is the tendon and there's the groove. So there's the bicipital tendon, there's the bicipital groove or the shaft of the humerus. And as you can see, the tendon is seen pretty well.

This is one of the older transducers we used to use. Here's one of the newer transducers, and you can see that the tendon anatomy looks so much better with the high frequency transducers.

Subscapularis Tendon

Next we wanna look at the subscapular tendon. The subscapular tendon comes again from the subscapularis fossa, and then it goes and inserts onto the lesser tubercle of the humerus.

Now if you look at the subscapularis tendon, it's more at an obli view. So when you take the transfer section, you want to make sure your long access to the fibers, and you also want to externally rotate the arm to bring the subscapular tendon out because what it does is the action of the subscapular is the medial rotation of the arm, and it stabilizes the joint.

There's the subscapular tendon with the muscle, and you wanna scan along the long axis fibers of the tendon. And now what you're looking at is the tendon. When you scan, there's a subs capillary tendon with the biceps tendon there. And when you move the arm out, you will find that the subs capillary tendon moves out all the way towards the biceps tendon.

Here's an example of a tendon of the subscapularis in a long axis view, but this is a short axis of the tendon itself. So what this is doing is basically cutting these fibers across, and what you're looking for is within this, there's the muscle and the tendon junction.

Supraspinatus Tendon

The next we'll look at the supraspinatus anatomy. This is basically the most important thing you want to look at in the shoulder joint. And what you're looking in this picture is the origin of the supraspinatus tendon or the muscle and the insertion of the tendon on the greater tuberosity. And what the ra spinatus does, it elevates the arm for the first 15 degrees. So most people who have ra spinatus problem basically have problem elevating the arm the first 15 degrees.

Here's the supraspinatus anatomy. There's the muscle coming from the supraspinatus fossa, and then you're going onto the supraspinatus tendon that goes and inserts onto the tuberosity. And there's a schematic diagram showing the supraspinatus muscle, the tendon, and what you find is the acromion sitting on top.

So when you scan anteriorly coming from there, you're going to hit this bony landmark that's gonna shadow onto the supraspinatus tendon. So in order to move away from this bony landmark, you have to position an arm in a particular fashion.

Here's a schematic diagram of the spi tendon area. What you see on top is the skin subcutaneous fat, deltoid muscle subdeltoid bursa, and then you see the cough tendon. And what you see underneath that is basically the humeral head and the cartilage.

If you look at the supraspinatus anatomy in transverse, you again look at a very similar structure going from the supraspinatus, subcutaneous fat deltoid, muscle subdeltoid, bursar cuff tendon, and the humeral head with the art articular cartilage. This is sometimes also known as the rim of a tire sign because it looks like the rim of the tire with the layers going in centric circles from the outside to the inside.

This is the anatomy where you are looking at the supraspinous muscle and the infraspinatus muscle. Now this is the position that you want the patient in because what that does is it brings the supraspinatus tendon more anteriorly and it goes away from the acromion and then brings it out. So you can do the scanning of the tendon.

And here's an example where the arm having been ex extend, moved backwards. You see a long axis of the fibers of the supraspinous tendon. This is the axis. And what you're looking for in here is basically the spi muscle and the tendon going in, inserting onto the greater tuberosity. What you also see from here is subcutaneous tissue, deltoid muscle subdeltoid bursa, supraspinatus tendon. This is the cartilage and the humeral head. And what you also notice is the humeral head. That's much smoother because it's a normal anatomy.

Infraspinatus Tendon

Next we move on to the infraspinatus tendon where the origin is in the infraspinatus fossa. So this is the infras test fossa, and it inserts onto the greater tuberosity. There is the infras muscle going and inserting onto the greater tuberosity.

Now what you wanna make sure is when you scan the infraspinatus tendon that you go a little bit deeper. When you go from anterior to the posterior anteriorly, you were scanning the srap tendon inferiorly. You're scanning the infraspinatus tendon posteriorly, and you want to make sure that your depth is adjusted to reflect that anatomy.

So here's the infraspinatus tendon will flip it around so it matches with the anatomy. So there's the infraspinatus muscle and the tendon infraspinatus muscle and the tendon. And what you see up here is a tendon coming and inserting going over the humeral head and getting inserting onto the greater tuberosity.

Here's the infras tendon again, as you can see, going laterally onto the other side. And in insert onto the humeral head, you can also look at tus minor, which is basically again coming a little bit lower compared to the infraspinatus, and that's the tend anatomy of for the muscle and the tendon and the insertion. This is a that shows both the infraspinatus muscle and the tus minor in one section.

Other Structures

There are other structures in the shoulder that you can evaluate apart from the rotator cuff and the biceps. And those are CHRO clavicle joint. What you're looking for is basically the acromion and the clavicle. And this is a very superficial structure, so you want to make sure that your depth is very shallow. And what you're seeing up here is the clavicle and the acromion with the ligament on top.

You can scan this area for looking for fluid, for inflammation, and also for this is also a good site for injection for the pathology in the AC joint.

A couple of other things you can look for. You can look at the spinal glenoid notch, which is present there. And also you can look at the posterior labra, which is a bright hyper echoic structure. That's the bony glenoid. And what you also find in this area basically is you can find fluid. Sometimes you can find ganglion cyst, and also this area is very vascular, so sometimes you can find vascular signals when you do doppler.

You can also look at the highline cartilage. What highline cartilage is important in the region that many times when you have tendon pathologies anteriorly, the highline cartilage will become exposed up top and sometimes it appears like a bright linear ecostructure. What you see underneath is basically a humeral head, and you can see this is a normal humeral head because it has nice smooth contours.

You can look at subdeltoid bursar, which is this black area within the anatomy, and sometimes the tendon itself is normal and the bura is inflamed. So what you get is the subdeltoid bursar or the bursitis or inflammation of the bursar where you have fluid within the bursar or the bursa is thickened, and you can get increased vascularity within that area.

Thank you.