How To: Ankle and Foot Ultrasound - HD

Musculoskeletal Ultrasound of the Ankle

This is nra.
I'm from Tamba Jefferson University.
We'll be looking at today at the musculoskeletal
ultrasound and specifically the ultrasound of the ankle.

Patient Positioning

The way we scan the ankle is the patient in the prone
position, with lying down flat on his belly,
and then with the foot hanging away from the table.
This way he can scan most of the posterior, medial
and lateral, and also it's easy to compare on the other side.
The other thing you also do is once you're done the
posterior medial and the lateral, you can have the patient sit up
and do the anterior portion.

Achilles Tendon

We usually like to start with the achilles tendon, which is posterior.
It's also a very big prominent tendon that you can scan very easily.
You want to optimize your depth, so you can see the tendon big enough
to look at the anatomy and the pathology of the tendon.
So you start within the meat of the tendon a little bit away from the insertion.
As you start scanning, you'll see that first you'll look at the sag image
of the achilles tendon from there to there.
And what you're looking at is basically the fibers within the tendon.
What you also want to make sure that when you're scanning from the top,
these fibers at right angles to the top portion of your pro,
because the sound beam comes at 90 degrees and hits the fibers,
and that makes it appear hypoechoic and has that fibrile pattern.
And the reason that's important is because in case you have a pathology,
the first thing that happens with the tendon usually is they test to get hypoechoic,
which is basically darker image.
And that helps you diagnose very subtle pathologies or tendonitis.

So let's look at the Achilles tendon first as we scan from the proximal,
or the cephalad going down coddle.
So there's the achilles tendon.
As we are scanning from the top to bottom, you can see the fibrile pattern look normal.
And you can also see they're very uniform.
So as I scan down from the sag going down towards the codal aspect
or towards the insertion of the tendon, and what you're doing now is,
as you can see, the tendon fiber stray pretty much perpendicular to the top part.
So I'm gonna keep scanning down till I hit the calcan, which is this pony prominent there.
And what you're doing with the calcan is that's where the insert the tendon insertion takes place.
So you can see the tendon coming up there, coming down and inserting onto the calcan.
Now, when it inserts, a couple of things happen.
One is the tendon gets very narrow, and the other thing that happens,
the insertion point, the tendon starts to curve down.
What that means is basically now the tendon fibers are not appendicular to the top part of the probe.
So sometimes you'll get an image where the tendon starts to look dark.
That's not to be confused with pathology,
that's just with the tendon appears because it's curving down.
What you want to do in that case is you want to angle the probe from the top half
so that now the tendon fibers are propend killer.
And you can see how it becomes hyper echoic again.
So that's just a normal insertion point into the calcan.
You do the same thing again, come back out again, look at the tendon in long axis
and then turn 90 degrees to get the transverse view.
Usually I call it like going from a 12 o'clock to a nine o'clock position for the pro position.

So as we turn transverse worse, what you will see is the tendon appearing oval,
and you have to just center the probe over the tendon because the tendon can be off axis a little bit.
What you also see on both sides is a drop out of echos and they're just normal
because the probe is not in touch with the tendon or the ankle because the tendon is pretty narrow
compared to the size of the probe, that you're scanning with.
So you center the probe again on the tendon, and what you see now is the tendon very nicely seen
and the tendon appears oval.
That's something to remember because most tendons appear oval when they're normal.
And what you see also is this nice bright structures within which is normal.
The first thing that happens when the tendon becomes abnormal, apart from the tear,
if it's inflammation, the tendon becomes more round.
And that's in a subtle change that you can catch when you are looking at a tendon pathology
like inflammation or tendonitis.
So here's a normal tendon.

So you're going to be scanning up and down, going proximal or more towards the head.
And what you see appearing below is just the muscle belly.
That's just a normal muscles always appear a little bit darker than the tendon.
You can see that difference between the tendon and the muscle.
As you start to scan down a little bit lower, I'm trying to stay straight onto the ankle tendon.
If I do not stray at 90 degrees, I can show you how the tendon tends to become dark.
If you scan at that angle, what you would find is the tendon appears abnormal,
but that's just the angle at which the probe is hitting or the beams is hitting the hitting the tendon.
And you can correct that just by angling the probe.
As you keep scanning down, you'll see the tendon again, go over the calcan where the insertion point is,
and as you come down this the tendon and you will see the calcan up appear below right there,
which is more echogenic and it shadows.
So the tendon is above it and it's going to come and again, insert onto the tendon.
What happens as it insert again, same thing happens because it's curving down,
you lose the 90 degrees.
So you wanna make sure that your tendon is not hypoechoic, which is just atrophy,
which is not hitting the probe, hitting the beam at 90 degrees.
And you can also see the bony structure, which is very uniform.
Sometimes you can see ossified or calcifications within the tendon or at the bony landmark.

Medial Aspect: Posterior Tibial and Flexor Digitorum Tendons

What you do is you go next medial.
So you're looking at the medial moles and you're putting the probe down just next to the medial moles.
And what you're finding now is you can see the two tendons, which is the posterior tibial and the flexor digitorum.
The posterior tibial is the bigger tendon, and the flexor digitorum is a smaller tendon.
Same thing. Again, that's the medial modulus that you see there.
And then as you scan down, what you find is the tendon appears normal and oval,
as we talked before, that that's a normal appearance of a tendon.
What I do at this point is usually turn long axis because the tendon is usually going to go down,
to the foot.
So in the long axis, the tendons are going to appear side by side.
And there's the posterior tibial tendon, which is seen very well in the long axis with the fibers,
going horizontal.
Now what you also see usually in many tendencies is a hypoechoic area on both sides.
That's just a normal sheath or the tendon sheath that you see.
Most tendons have tendon sheath.
The achilles does not have a tendon sheath.
So what happens many times you'll have an inflammation of a tendon sheath and not the tendon.
So you have to be careful to make sure that the pathology or the pain is coming from the tendon
or the tendon sheath.
Otherwise, you can mistake the tendon pathology for tendon sheath pathology,
and that's called the tendon sheath. Pathology is called as the tenitis.
Again, this tendon looks normal.
That's the posterior tial tendon, and that's the bony landmark underneath it.

What's going to happen as you slide down, you're going to have the ankle of,
or medial myles of the ankle where the tendon starts to curve down.
And as it's curving down, you will see that you can follow this tendon.
Most of the time we do not follow the tendon unless there's a pathology.
But for posterior tibial, it's usually important to make sure that you follow it
because you do find a lot of pathology within the posterior tibial tendon.
And what happens with this tendon, it goes and inserts onto the navicular bone,
which is on the medial aspect.
So there's the distal portion of the posterior tibial tendon.
As you move down, you can see it's, it's going to go and insert onto the navicular,
and there's the navicular coming in on the right side of your screen,
which is the bone that looks calcified, obviously.
And then there's the insertion from the navicular from the tendon posterior tibial tendon to the navicular.
This fibers, because they're spread out from the insertion point,
it's normal for them to appear, in spread out.
So what ends up happening in this case is you're getting the fibers going from top up here
and bottom going down.
So you lose that 90 degrees that you normally see within a tendon.
Sometimes it's normal to see a little bit of fluid there, it doesn't have any,
but sometimes you'll see a little bit of fluid, which is just normal.
Then again, when you go transverse, you'll find there's a second tendon there.
That's the flex digitorum, which is right here.
So we look at that in long axis, and that's a smaller tendon that you see.
And there's the f flexor digitorum, which is a smaller tendon right there in long axis.
Again, it has the same fibrile pattern, pretty uniform again as it goes down.

Lateral Aspect: Peroneus Longus and Brevis Tendons

What you can do next is go to the lateral aspect of the ankle.
And what we look at now is the two tendons, which are called the porous longus and brevis.
Now what you want to do is when you go to the lateral side, again,
there's the lateral moola that you can see on the bony landmark there.
And what you want to do is stay pretty close to the lateral moola
and almost angling straight up and down, not angling too much medial,
that's one of the common mistakes people make and you don't see the tendon.
The other difference between the lateral and the medial tendon is the lateral tendons on top of each other.
So if you look at these two tendons, which is the parus longus and the brevis,
you can see how they appear on top of each other, not medial and lateral,
like it was on the medial aspect.
So the, the reason it's important to remember for two reason,
one is if you're looking in transverse, you're going to see them on top of each other.
Sometimes they call it the stack of pancakes.
And what you're looking for, apart from the tears on the, on the lateral aspect,
is to make sure that the tendons don't subluxate onto the area above this point.
That's a very common occurrence that can happen with the peroneal tendon.
They basically tend to subluxate the patient sometimes can, will give you a history
that the ankle, he hears a clicking on the lateral aspect.
What happens in that case is this portion goes over the, this hump here on the lateral modus
and slides to the other side and then comes back.
Sometimes it's painful, sometimes it may not be painful, but you'll definitely hear a quick,
you can also do this manure when you're doing the scanning.
The other thing to remember, because they lie on top of each other,
you're going to see them at one the same time when you do the long axis.
So when you turn the long axis of the tendon, what you see now are both the tendons on top of each other.
The, there's the top portion, that's the bottom portion, that's the PROEs longest,
that's the brevis.
And what you see in between is basically the separation of the top portion
and the bottom portion of the tendon.
So I'm gonna follow this tendon down a little bit.
There's the lateral modus again, and you can see how the both tendons have a very similar appearance.
They look normal. There's no fluid around the tendon.
This is the tendon sheath again, and that looks normal.
Most of the time we don't follow these if there is no pathology distally.
But if there is, you can follow that all the way to the insertion at the base of the metatarsals.

Anterior Aspect: Anterior Tibial Tendon and Joint

What we can do now is have the patient sit up.
So we can look at the anterior portion of the tendon, just bend your knees And good.
So we are gonna, looking at the anterior joint, we look at the anterior TBL tendon and then the joint.
So if you go transverse, what you'll find is the anterior TBL tendon is the most prominent tendon
you can visualize, which is right there.
There are other tendons that of the digitorum that we don't usually look at unless there's a pathology.
But it's always good idea to look at the anterior tial tendon.
It's very prominent tendon.
Sometimes they say this doesn't get injured as often because it has a good blood flow.
But we did find quite a few pathologies with ankle anterior tibial tendon.
And there's the tendon in transverse.
Again, you can see how it'll appears oval and has a very similar appearance to the other tendons.

What we'll do now is look at the long axis of the tendon.
So there's the anterior tial tendon in long axis.
That's the proximal or the cephalic can, and that's the distal end.
And we'll do is go down.
What we'll do, we'll come back later and look at the joint, which is down here,
but right now we are focusing on the tendon above.
And you can see how it looks hypoactive because you haven't really focused on this, this area.
So look at the anterior tibial going down and that appears normal.

In that same position, what you want to do is if the anterior tibial tendon is normal
and the patient still has pain, you want to look at the joint underneath it.
And what you do in that case is obviously you'll have to drop the frequency if it's available
to a deeper level, and also to make sure that the focal zone goes down, Down a little bit.
That's good.
And what we'll do in this case, we'll increase the depth one notch and which is,
as you can see, we change the depth and then we'll bring down the focal zone to the posterior part.
Maybe turn the gain up a little bit posterior.
So what you see now here is the bony landmarks, and the, the anterior ankle joint,
the dome of the tails and the T TBI is seen there.
And this is the joint.
And you can see the cartilage within the joint.
This area, sometimes you can see fluid within this joint in that area
or sometimes you can see is calcified bodies that can cause pain.
And as seen before, there's the anterior tibial tendon.
In this case it looks normal.
There's the joint, that's the TB on top and coming down to the do of tails and the cartilage.

Conclusion

So that's basically concludes looking at most of the major tendons of the ankle.
As you can see, most of them are pretty easy to look localized.
Most of them have a very nice appearance.
They also, they run straight up and down.
If you look at all the different joints compared with the shoulder, elbow, knee,
and the ankle, the ankle joint usually is a little bit easier to scan,
especially if you're new because most tendons on the outside of the joint
and they all range run straight up and down.
So we looked at things posteriorly, we looked at things medially,
we looked at things laterally.
And then anterior, and that should be the basic ultrasound scanning of the, ankle, ligaments and tendons.