Transcript
- Okay, welcome everyone
to our webinar on carpal tunnel evaluation.
Before we begin, just please be advised
that all attendees are muted.
You're welcome to type in your questions in the q
and a box in the toolbar located either at the bottom
of the side of your screen at any time during the webinar.
We will conduct a q
and a session at the end of the presentation
and demonstration.
This webinar will be recorded
and available archive for future reference.
Our presenters today are Daniel Shelton and Bill Medford.
Daniel Shelton is the director of our MSK market development
for Fujifilm Sauna Site.
Daniel has spent 16 years as a dedicated MSK sonographer
and 10 of those years have been here at Sauna Site.
Now he leads the MSK market development where he works
to spread the word about benefits of point
of care ultrasound Bill Medford is the lead MSK specialist
for Fuji Thumb Cyte with 40 years of experience
as a sonographer, including 22 years specializing in Ms.
K Sonography. Bill is an expert in using POCUS across the
breadth of MSK specialties.
At this time, I'll hand it over to you Daniel.
- Thanks Lisa and thank you everybody for joining us.
It looks like there are still a few folks rolling in here.
So what I'll do is just kind of open this presentation
by thanking everybody for being here
and thank you for your time.
We still see the numbers going up,
but just know that there's a lot
of content in this slide deck.
A lot of it is just for reference.
So when you go back to the Sono Site Learning Institute,
you'll be able to review a lot of the notes
that are on the side of the screen
where the origins and insertions are.
For example, so I'm not gonna be reading the
slide word for word.
I'm going to be discussing basically what's relevant in
that slide for examining the carpal tunnel
practically and quickly.
So thank you all again for being here.
I'll be doing the presentation.
My name's Daniel Shelton again
and on the live scan today we have Bill Medford, our
lead MSK specialist up in the Seattle office.
So displayed here is the Sono site PX
where all the images were taken for the slide content today.
Keep in mind to do a diagnostic level carpal tunnel exam,
it is recommended that you choose a clamshell machine
or higher and I understand that
that can very much range from system to system,
but things that you wanna look out for, color sensitivity
and your frequency.
So today we'll be scanning at 15 megahertz
for the general survey of the carpal tunnel
and you'll see some images at 19 megahertz.
But I've chosen to save a lot of the 19 megahertz images
for bill's live scan
because I think it's most impressive when you're
able to scan live.
Remember, you have a chance to go ahead and ask questions
and we'll save those for once the slide content
and the live demonstration has been completed.
But have those questions ready and type them into the q
and a portal on the right side
of the screen here is the L 19 scanning a
carpal tunnel case with swelling.
The diameter of this the, the internal circumference of this
median nerve is roughly 16 millimeter squared.
Just to give you a reference.
So anytime you suspect there's nerve swelling, go ahead
and throw your color powered Doppler on there
and see if you've got any internal vascularity
that would not normally be detected in a normal nerve.
And it may just add your clinical picture.
Looking at carpal tunnel, it's responsible for over 90%
of compressive neuropathies indications can be hand
weakness, reduced grip strength, pain, tingling, alteration,
and temperature and control of the wrist and hand.
Other things to look for
besides swelling, there's flexor tenino synovitis,
there's ganglion cysts base occupying masses
and post-surgical intervention complications like we see
here at this distal radial fixation.
So we have this big metallic artifact casting this huge
shadow here over the distal radius
and look at the flexor tendons rubbing.
While that's not immediately within the carpal tunnel,
if the patient is exhibiting those symptoms of some sort
of median nerve entrapment,
I would look at the surrounding flexor tendons
and see what's, what's maybe causing those to swell
and flare and press against the median nerve.
So it just could add to a further clinical picture.
Having ultrasound is really nice
'cause post-surgical interventions are not gonna cast
artifact into the areas of interest.
For example, like you would in MRI, we're not seeing that
that bright or that really black halo sign
that we see in an Mr.
Overcasting. The anatomy first things first.
Any time or scanning musculoskeletal ultrasound,
I'm always telling people to start off scanning bones,
ignore all of the soft tissues
until you see really nice bony landmarks
and then work your way from the deep part
of whatever you're scanning in MSK work your way
superficially so you'll never be lost.
The soft tissue landmarks will constantly change an M ms K
ultrasound but will will not usually change much are the
bony references.
So once you have a good foundation of bony references,
that's when I want you to start worrying
about the soft tissues.
So first thing on the carpal tunnel,
we're gonna find the biggest bone in the area is the
radius, number one.
Number two, we have the ulna scaphoid pisiform marks our
inlet and you can see those labeled three and four.
And then we're gonna go to the outlet
of the hamate and the trapezium.
Once you're familiar with those bony landmarks,
then we'll work our way down towards
where we're gonna start scanning our our media nerve.
So in this slide deck you're gonna see a lot
of notes on the side of the screen.
I'm not gonna read 'em all, but we are gonna build a
carpal tunnel today.
So we're gonna start with this 3D CT
and we're gonna work layers into that superficially so
that we can better understand
what the cross section will look like.
So as an anatomy survey approximately,
we're gonna look at the pronator quadratus first.
This is a very large muscle
and we're gonna scan that and you'll see what it looks like.
But that's the first level that we're concerned
with taking a measurement if we suspect some sort
of median neuropathy also traveling through the contents
of the carpal tunnel, but not a part
of the proper carpal tunnel itself
as the flexor carpe radialis.
So the flexor carpe radius does travel up over the sca void
and that's very noticeably not a part
of the carpal tunnel when we're scanning.
But as you go distally through the carpal tunnel,
you can see right here at the trapezium tubercle how close
that flexor carpe radius rests up against the trapezium
tubercle and cross-section.
You'll see that it's actually sitting in a little tunnel.
The trapezium tubercle has a little tunnel
and it's to housed the flexor carpe radialis
and it is external to the carpal tunnel content.
So just know that there is a little tunnel here called the
FCR tunnel, flexor Carp radiology tunnel.
It has its own ret ulu
and it is not a part of the carpal tunnel.
However, if your transducer is angulated
a little bit too distally
or proximally, this may look like a cyst
and you don't want to call this a fluid collection.
So it's just something to keep in mind right there at the
wall of the carpal tunnel.
There may be a little black structure there.
You don't wanna call that a ganglion cyst
just internally to the carpal tunnel.
Content towards that is the flexor pollis longest.
Now the flexor pollis longest is within the carpal tunnel,
but does have its own tendon sheath.
So it is not a part
of the bursal slash tendon sheath complex
that we're gonna discuss in a minute.
But it does travel through the
contents of the carpal tunnel.
It is a part of the carpal tunnel.
And to isolate this particular tendon when you're scanning,
just flex your thumb
and you'll see it move independent of the rest
of the structures in the carpal tunnel tunnel.
Next we have the flexor digitorum profundus layer,
which is the deepest layer of the carpal tunnel.
It's gonna hug the floor of the carpal tunnel
and then it's just superficial to
that is the flexor, oh, I went the wrong way.
Flexor digitorum superficialis.
So they run in parallel
and they're gonna branch out to digits 2, 3, 4, and five.
Immediately. Superficial to that, we've got our
bursa slash tendon sheath complex.
Now these are for lubrication in the carpal tunnel,
but it can swell too.
So if there's any excess volume in this complex,
it will cause pressures that are going
to press against the median nerve and may cause entrapment.
Superficial to that, we've got the median nerve
and it will travel through the carpal tunnel
and there's variations of the median nerve
and we won't go into that today,
but I think you'd be really, really impressed if you were
to look up all the different variations of the median nerve,
just how different this may look when
you're scanning with ultrasound.
So just be aware that this is the most common appearance
of the median nerve anatomically, but there are variations.
This can bifurcate unusually proximally right up
through the carpal tunnel.
And sometimes way back here at the pronator quadrats,
the median nerve can already be bifurcated.
And we'll look at one of those here in just a minute.
The transverse carpal ligament, it is a complex,
it does have an origin, it does have an insertion,
and it is not just one big ligament.
So this has been described to originate at the hook
of the hamate, travel to the trapezium from the trapezium,
jump over approximately to the pisiform.
And from the pisiform it will eventually
terminate at the ca fight.
You'll notice that it does look complicated around the f
flexor carpi radis.
And when we're ultrasounding you're gonna see that it,
it almost starts to group in right there with it.
It does travel up and over the flexor lysis longest
and takes a sharp dive down
and we'll see a a very,
very sharp pronounced black shadow separating the flexor
lysis longest from the flexor carpi radiologist.
Once we get to that on the live scan, superficial to
that immediately is a tendon called the erris longest.
It travels right over the flexor reticulum
but then branches out to the palmer.
A neurosis. If you're fairly new to carpal tunnel anatomy,
this is a really cool one to look at superficially
because it's also a palpation landmark.
You can just place your pinky and your thumb together
and then flex your wrist
and you should feel a bulge right here at the wrist crease.
And that tendon is the palmer,
or sorry is the palmer's longest.
I went ahead and made that semi translucent.
So we can see how it relates to the structures underneath,
but ulnar to the Palmer's longest
and the rest of the carpal tunnel.
Here we've got another reticulum,
which represents Ian's canal.
Ian's canal, its insertion port parts are the superficial
flexor reticulum and the pisiform, it is its own tunnel
and has its own neurovascular
structures traveling through it.
And its contents are the ulnar nerve and the ulnar artery.
Now you can see that the slide just got
a lot more complicated.
There are branches of each of these afterwards.
And for a future PowerPoint presentation,
we will discuss more advanced nerve scanning, not only
of the carpal tunnel and all of its variations
and it's superficial sensory and motor branches.
But we'll talk about these other nerves like the radial
nerve and the ulnar nerve
and all of their little variations too.
But that's not for today. Switching over to cross-section.
So now that we're in cross-section,
you can see the reference of
where the transducer is located here on the upper right.
So this represents a slice of where we are here.
So if you remember back in the stripped away anatomy,
we had the, we had the pronator quadratus layer here
and that's where we're gonna start with
where we're gonna begin looking at the median nerve.
So here's where it's gonna be sitting right over the radius
at this level, just over this interosseous membrane level
here is all the groups of the flexors
before they, they really bunch together.
Now we're gonna travel distally just a little further
to the inlet of the carpal tunnel.
On the radial side you'll see the scaphoid on the ulnar
side, you'll see the pisiform.
So once I see the pisiform, I always look
for the pisiform first.
I then just pivot the transducer radially
until I see the Sid.
Once I see the scaphoid,
then I worry about the angle at which I'm
imaging the carpal tunnel.
This is a very angle dependent structure
and I have a visual on that coming up
after we get through what the landmarks look like.
So here you can see that flexor retina aum traveling down
to the inferior and anterior margin to that pisiform
and the most anterior margin of the, the pisiform
where the flexor carpi ris would insert too.
So here's the contents of Ian's canal
and the flexor reac makes up the floor of Ian's canal
and comes up and over the median nerve.
And you can see that that median nerve is
touching the flexor retina aum.
That's, I mean, there's no space
between the flexor retina aum and the median nerve normally.
And then as the flexor retina aum traverses radially
to the scaphoid, you can see the flexor lysis longest
immediately hugging the wall
of the contents of the carpal tunnel.
And the flexor carpi radial is sitting outside of
that carpal tunnel.
As we travel more distally, same thing.
Ulnar is on the right side of the screen.
Here's the hook of the hamate, this big prominent shadow,
the art, the ulnar artery is now resting on top
of that hook of the hamate.
That's another really good landmark here.
And, and once we're in the live scan bill,
we'll discuss what's called the anatomical safe zone for
ultrasound guided carpal tunnel release procedures.
It's a really, really nice landmark
to be discussing this zone.
So once bill is live scanning, we'll remind him
to make sure he's covering this really,
really important view here.
But you can see the median nerve is now changed shape, okay?
So it naturally flattens out
and that's why you don't wanna call that the level
of compression just because you see it flattening out.
In fact, a lot of times you'll,
you'll see a change in the shape of the nerve
where it's starting to to bifurcate twice basically.
I don't know if quadric cate's a word,
but that's what it's gonna do
and it's gonna turn into these other branches
that eventually become traveling over to the digits.
Long axis is a very helpful view.
It's not the most prominent diagnostic view though
for entrapment because
that median nerve does flatten naturally
distally through here.
So what we use the long axis view for is not necessarily
for measuring, but we're using it
to put the image into clinical context.
Do we see swelling such as tens synovitis?
Do we see fluid collections, ganglion cysts
where they originating like you saw
that post-surgical complication picture
pressing against the flexor tendons very easily.
That's what we would use the long axis image for, not
so much for measuring.
Now let's get into some carpal tunnel scanning tips.
These are key to getting a good image after you've found
and established your bony landmarks
that we've already discussed.
So here's our pisiform and our scaphoid.
This is what most people land on this big red one.
And notice that the, the correlation
to the slice on this MRI over here is
that it's perpendicular to the skin.
This is the most common thing
that I see when beginners are getting into carpal tunnel
scanning, is that they stay 90 degrees to the skin
because they were told, Hey, I gotta stay 90 degrees
to my structure, forgetting
that the carpal tunnel contents dive away from the probe.
So what we have to do is angle the transducer towards the
fingers or the handle, I should say, towards the fingers.
And that should brighten up the internal
contents of the carpal tunnel.
You can see the superficialis layer and the profundus layer.
In fact, what you're seeing is it separates,
see down here against the carpal floor,
something we didn't discuss
or the ligaments, there's lots of ligaments
that hug the carpal tunnel floor
and we won't go into naming those today,
but they are anti isotropic.
So you don't wanna call this a fluid collection down here.
You don't wanna call this a fluid collection.
Incidentally, here's the flexor lysis longus
and the flexor carpe radius.
And you can see how the carpal tunnel,
flexor re aum dies vertically right here.
It's a very harsh dive. It's perfectly inotropic.
This is not fluid.
This isotropic non reflection back to the probe.
So you can see the difference in these two images
and how you might call this a fluid collection versus the
more 90 degrees to the, to our actual target of interest.
And this brings me to a point, if you were
to tilt this transducer here, as we travel
and traverse down the carpal tunnel,
you're gonna notice the shape of the carpal floor change.
The walls of the carpal tunnel are gonna change.
So I, I did a little animation here
through the ulma and the radius.
We would stop at the pisiform pivot the other side
of the probe at the scaphoid.
And then we're gonna, we're gonna angle so
that we're following our structures 90 degrees distally.
So here we have the hook of the hamate trapezium tubercle
back to pisiform
and we'll let the animation finish back
to scaphoid radius ulna.
So use this recording as a reference
and study your surface landmarks of your carpals
and you'll never be lost in the carpal tunnel.
Other scanning tips when I'm scanning nerves or tendons or,
or very, very small branches of nerves,
scan in little one inch windows, little proximal
to distal segments.
Don't, don't just set the probe over the area of interest
and be still, this is a, this is ultrasound
so you're gonna wanna make it move.
So anytime you can make anatomy move
or scan through it, you're gonna wanna do that.
So in this case we have the median nerve
resting over the radius.
And all I'm doing, because this is a zone where
tracing the median nerve gets a little bit hard it,
it sets radial to the flexor tendons at the level
of the pronator quadrat.
So this can be, this can kind of give you a headache
'cause you'll notice that the nerve travels upward
when the nerve travels upward.
You have to match that angle and sweep upward.
So keep that in mind. Another thing is
as it travels upward, it may be highly in isotropic.
So as we follow the the median nerve,
you wanna just maintain perpendicularity.
So here we leave the flexor tendon level
where the muscles are and we're traveling into the carpal
tunnel and you can just see
how the shape of the nerve changes.
Incidentally, a bullet point that I did not put here,
but I'll go ahead and mention it now
'cause we get this question a lot,
is why is the median nerve so bright here
and why is the median nerve so dark
here once we get up into the tunnel?
And the answer to that is the overlying musculature
in a healthy muscle is gonna
further enhance the sound wave over the median nerve.
It's gonna amplify whatever sound is passing through there,
like an acoustic lens.
If, if you're familiar with looking at fluid collections
already, like joint effusions
or if you're already familiar with abdominal scanning
or pelvic scanning, what a bladder does is
that it's gonna further enhance whatever
structures are underneath it.
Basically that's what's happening here is relative
to the surrounding tissues,
the median nerve is now being over.
I'm gonna pull the video clip back,
go off script a little bit but, and I'm gonna hit pause,
but right here this muscle is acting
as an acoustic amplifier basically
and it's enhancing the sound waves that are underneath it.
So basically this, this water-filled muscle,
this fluid dense muscle is making the median nerve look
that pretty when you go superficially you're really gonna be
burdened by your angle to get the best image you can.
So now we're entering the carpal tunnel there.
You'll notice that the median nerve is much less impressive
in terms of brightness
and you're really gonna be working on your angulation
to get these, this fatty epi nearium
and all the little fales, the walls of the fales
to echo back 'cause the fales are dark.
Other things to consider bifid median nerve
which we see here.
Persistent median artery always throw on your color.
This is just a normal median nerve
with a persistent median artery.
Normally I see 'em together,
but in this particular case I did not see another
bifurcation at 19 megahertz.
We have a video clip here where you can see both segments
of the bifid median nerve with
that persistent median artery sitting right underneath it.
So this was taken with the L 19 transducer
and notice the tendon detail
and the intra fascicular detail we get outta 19 megahertz
versus 15 fifteen's.
Great, we were, we we loved 15 for a long time
until we had this 19.
Another thing to consider is the mobility
of the median nerve when it's in.
So if the nerve is being compressed,
what's causing the compression?
If I'm holding a coffee mug for more than three minutes,
this, this squeeze and the kind of curl I do
and I'm holding a coffee mug, my hand goes numb in about,
in about less than five minutes
and this is the action that's causing that.
So if I'm squeezing and curling, you make a fist
and curl kinda like we did
with the Palm Air's longest action, but we're gonna squeeze
and curl, watch the median nerve, does it travel
and get stuck between those heads of the superficial layer
of the flexor tendons.
And that's what we're seeing here.
So it is just another part of the story.
Just something else to try to paint the rest
of the clinical picture measurements we're gonna measure at
the inlet of the carpal tunnel,
if it is less than 10 millimeter
squared, we're in good shape.
If it's between 10 and 12 millimeter squared, that's
where you wanna go back to that pronator quadras.
Take that reference measurement.
If the pronator quadratus measurement
and the inlet measurement differ by two millimeter squared,
that's been reported as a positive indicator
for swelling of the median nerve.
If it is bifid, you can add the two segments together.
A positive indicator is if both parts are greater than four
millimeter squared, again,
long a long axis measurements have not been very reliable
for clinical decision making.
Another indicator could be transverse carpal ligament
bulging and that happens
to be most studied down here distally at the most
outlet part of the carpal tunnel.
And that's where the hook of the hamate
and the trapezium tubercle meat incidentally see
that black layer right there, that's our flexor lysis
or sorry, our our flexor carpi radialis.
And it looks black sometimes it's gonna look even bigger
than that but it's not a cyst or anything.
But you're gonna take a measurement, a caliper from here
to here and then you're gonna measure right in the middle.
And if that Boeing is more than two to four millimeters,
it's been recorded as another positive indicator
of swelling of the carpal tunnel.
I've got a quick reference slide just for the recording
and for you guys to be reminded to go back
to the learning institute and catch these recordings.
And we also invite you to check our
upcoming webinar schedule.
These are happening monthly, sometimes weekly,
but the, the schedule is constantly being updated
and we invite you guys to join us
for the future scanning topics.
That concludes the actual slides.
We wanted to bunch all those together
before we hand it off over to Bill.
So keep those questions ready to go in the comments section
or the the q and a and I'm gonna go ahead
and turn it over to Bill Medford
and he's gonna be scanning live from Seattle.
This is live, so as you're asking
questions we'll be watching those.
If it's something that needs to interrupt the live scan,
we will interrupt Bill.
So I'm gonna go ahead and turn it over to you, bill.
And let's see, let's see how the median nerve scans today.
- Very good, thank you Daniel.
That was an excellent overview of the carpal tunnel.
I'm going to do my best
to parallel Daniel's presentation in the interest
of consistency.
And so without any further ado, we'll begin.
So what I like to do is use a gel bottle
to place under the dorsal aspect of the wrist
that helps you maintain the, the best angle
to assess the carpal tunnel.
As I'm working from proximal to distal,
I'm gonna begin scanning by using the 15 four megahertz,
50 millimeter wide footprint transducer,
which gives us the ability to view the greatest amount
of anatomy from side to side and proximal to distal.
I'm gonna begin scanning in the short axis plane
to the lower arm beginning approximately at the quadratus
fem pronator quadratus.
Before we do anything, we have
to select the transducer we're going to use.
So I'm gonna begin by selecting the L 15 four transducer.
I'm going to use the, the nerve setting.
I'm scanning the right wrist.
So patient right is to screen left
and as you can see, we are up at the level
of where we see the radius.
I'm gonna bring an arrow up.
We're at work from deep to proximal.
We're going to see the radius and the ulna.
And then we're going to see this pin pattern
of longitudinally oriented fibers of
the pronator quadratus.
It's at this level where we're going
to identify the median nerve in
between the two flexor muscle bellies.
And it's also at this level where if we're going
to look at the ratio of the median nerve proximally
to the entrance into the carpal tunnel, to the InLight
of the carpal tunnel at the level of the peace form
and escape for this is gonna be our first measurement
that we compare those area measurements to.
I'm going to decrease my depth
just a little bit to better frame my anatomy
and let's work distally.
Now as we work distally, we notice the central tendons
of some of these muscle bellies.
And it's important to understand
that if your gain is set too low,
this can look like peric tendinous fluid
and to the beginner is sometimes misinterpreted as fluid
as you get closer to the carpal tunnel.
So make sure your gain is up.
Make sure you follow these musculo tendinous
zones proximally to see that
that is not in fact per tendinous wood,
but in fact just normal muscle.
As we scan distally
and approximate the carpal tunnel, we see the median nerve
come through that tunnel.
Daniel describe
and come superficial to the muscles and now we see it here.
The, at this point I'm going to decrease my depth again
so that we see again the median nerve it takes on the
honeycomb pattern.
So characteristic of nerve as opposed
to the more bristle brush appearance
that you see in short axis when you assess
tenus structures.
If we work down, we come further.
We come to the twin peaks described by Daniel as the piece
of form on the ulnar side, the scaphoid on the radial side,
perched on the radius we see the flexor carpi radialis
and adjacent to that the flexor lysis longest.
And if you have your, your subject or patient flexor thumb
or his or her thumb, you can see it moving around there
relative to that provocation dynamically.
Also, while we're here on the radial side, we see the
the flexor retina ulu coming across
and the deep dive that it takes back to its insertion
and the resultant an isotropy that we recognize and
and do not want to mischaracterize as fluid.
Here we see with a better transducer angle the insertion
of the flexor retina re ulu onto the sca foot.
Back to the carpal tunnel itself, we see the,
the deep layer of tendons, the profundus layer
and the more and the superficialis tendons.
And as we move more ulnar, the ulnar artery,
the nerve and the piece of form.
So those are our proximal bony landmarks
and the proximal con contents of the carpal tunnel.
Again, remember
that the flexor carpi radis is
external to the carpal tunnel.
The flexor lysis longus is internal to the carpal tunnel.
Flexo lysis longus has its own tendon sheath
apart from the tendon sheath that covers the superficial
and deep layers of the profundus tendons.
You also want to recognize the very small
but noticeable flexor
or the palmer's longest tendon.
Not always present,
but most oftentimes is again, eons canal
artery, I mean nerve and artery.
Let's proceed from the piece of form distal now
and the next bony acoustic landmark that will run into,
oftentimes we need to apply more gel
as I'm having to do here.
A little crease in the palmer aspect of the hand requires
that you kind of fill it with gel.
I'm going to give myself a little more depth at this point.
As Daniel described,
the structures go deeper as we proceed distally.
So piece of form next bone acoustic landmark is
the hook of the hammock.
Here you see the ulnar artery.
Now it's easy with too much transducer
to compress the ulnar artery.
So letting up on the transducer pressure a little bit
and working at getting the appropriate angle,
it does get a little more difficult to get
that correct angle
as your distal in the, in the carpal tunnel.
So
there we have the hook of the hammock
and the median nerve.
And if you're entertaining ultrasound guided release
of the carpal tunnel,
these are the three strokes you wanna identify.
The ulnar artery, the hook of the hammock
and the median nerve.
And your transverse save zone is that measurement
between the ulnar side of the median nerve
and the hook of the handmaid and the
ulnar artery And the median nerve, whichever is less,
will define your transfers safe zone.
At this point I'm going to come, oh, let's go back here.
And again, the hook of the hammock,
your radial landmark then is
the trapezium.
And you see again here the anisotropic.
Now a little bit lit up.
Flexor lysis, lungs tend.
So at this point I would like to switch over to the
L 19 five transducer,
smaller footprint, higher frequency.
So we won't be able to image entirely across the
carpal tunnel, but this is gonna be more targeted
a a more targeted and utilizing high frequency,
higher frequency.
We're going to get increased image clarity
and greater confidence with what we're looking at.
I'm actually going to go to the nerve exam type again
to make, to provide a more contrast image which helps,
which makes the the dark darker, the brights brighter.
It helps better define the perineurium from fascial
and just helps nerves in general stand out a bit more.
So if we start out proximally,
we see again here it's very clear what is nerve
and what is tendon.
If down in the proximal carpal tunnel
we see the flexor carpi radis there perched on
the scaphoid flexor
lysis there.
And if we come more, come more medially.
Now if your patient can flex her second finger
and her third finger, you can see
how we can di differentiate each individual 10
and fourth finger
and fifth.
So isolating
and identifying each individual tendon is,
is really quite easy.
Now look also how nicely that we can follow the, the
flexor retina aum as it cut courses over the top
of the carpal tunnel
and as it comes
and inserts onto the Safeway there.
If we proceed toward the ulnar side,
we're now seeing Dion's canal with the ulnar artery
and the nerve come down to the piece
of form
again the ulnar artery and nerve
and as Daniel mentioned, this is for another time.
But you can follow that ulnar nerve
up and over the hook of the hammock
and see where it divides.
And you can actually see the superficial sensory branch in
the deep motor branch in a third branch here as well.
So higher frequency, better resolution,
more targeted assessment at what you're looking for.
This might be a transducer of choice also
for establishing the transverse safe zone as we see here.
How easily it is to demonstrate the median nerve,
the, the hook of the hammock
and establish the measurements important to be able
to do when considering ultrasound
guided carpal tunnel release.
Let's turn longitudinally long axis to the
carpal tunnel real quick.
Again, you can better differentiate,
you can better discern the characteristic sonographic
patterns of nerve versus tendon
with a higher frequency probe.
Here we see the individual basles in their length
of the median nerve, the underlying fibrillar pattern
of the flexor tendon following down into the carp tunnel.
We see it taking its deeper dive
and now at this level we can see
as we're scanning short axis to the flexor ulu
quite broad from top to bottom.
So we can identify the actual level where
the median nerve enters deep to the flexor ulu
and the ca and oftentimes see that thinning that occurs
as it proceeds through the carpal tunnel.
Another structure I want
to point out is we're scanning distally is follow following
the median nerve down through the carpal tunnel.
So we see the scaphoid
F-C-R-F-P-L
and median nerve, we're gonna follow the median nerve down
and as Daniel mentioned, as you get distally it flattens out
because it is beginning to get to that point
where it is going to splay into
the distal nerve branches.
The digitorum, we see the
trapezium there
and you see the flexor, we see the insertion
of the distal insertion
of the flexor retina AUM median nerve.
We continue to follow the median nerve again,
we see it flattening here
and dividing into those branches, distal branches.
Also at this level, if we direct the
thumb side of the transducer toward
the CMC joint
and we assess that again an important structure
to identify if you're considering ultrasound guided
carpal tunnel release is
thenar motor branch,
which takes off the median nerve vertically right here,
median nerve thenar motor branch coming
up and ultimately to rest superficial
to the thenar muscle.
Daniel, what have I forgot,
- Bill, that's outstanding stuff.
Could you go back to the distal carpal tunnel
and we're gonna clear up a landmark.
We had a question about right at the
trapezium at the distal tunnel.
Let's wiggle the thumb
and let's just clarify where that FPL L is versus the FCR.
So little thumb level, we got a FCR there, the little oval
and then the FPL l's inotropic
ish. Just just
- Right.
No, I think I called the FCR the yep. FPL L there, didn't I?
- That was the question and we got it cleared up on chat,
but I, I just wanna show people, you know,
one move the other doesn't.
So it's just super cool to just make it move.
'cause you know, we're, we're ultrasounding, there's
- Beautiful, there's the FPL - Beautiful,
- There's the FCR
and you're right, I called this the F,
not FCL fpl L here.
- Yep. - FCR here.
- Perfect. - And I called this the FPL. Correct.
Thank you for correcting me on that.
- You bet. And right now, let's see,
we've got a couple other open ones here.
Now the, we have a question about that Thenar motor branch.
Is this synonymous with the recurrent branch?
- I don't know the answer to that.
- All right, we'll follow up with that.
I believe it is, but,
and I've seen them referenced as the same thing
and especially the, the lead up to a bunch of
the slides that I was doing.
I believe they are the same name.
- Okay, I don't want to, - But if we find a different
- Yeah, I know something I don't.
And in the interest of accuracy
and accurate answer, I'm gonna say I'm not sure, sorry
- If, if we find different, I will follow up
with the question answer there.
We've got any more open questions right now there's no more
live questions going on, bill,
but I gotta say I loved that median nerve detail
and when I saw you in long axis, I could see
where the transverse carpal ligament ended at the
19 megaherz probe.
That was, that was neat.
That's hard to see on a lot of transducers.
It goes so distal sometimes it's hard to appreciate
how distal that transverse caral carpal ligament goes.
- Yeah, it is. And and with this, this kind of frequency,
you can make that distinction of
where it begins and where it ends
- As a reference.
Is that the right there? The,
the bony landmark you have in the far field,
which carpal bone do we have there?
- Let me go a little deeper just to better define this.
So this would be the capitate. Okay, where'd my arrow go?
I got two arrows. We'll use this one.
So we have the capitate, lemme that other one
- And then the other, after we get to show that part
of the ulu, could we show more details of the reticulum?
For example, maybe let's start,
maybe let's start at the scaphoid level and go, go short if
after you get your long axis assessment wrapped up,
but man, that's beautiful.
I can see, I can see a, the median nerve and where it ends
and I can see the transverse carpal ligament
where it begins.
- Yep. So this is also very useful if you're considering
doing hydro dissection of to be able
to see the actual retina aum.
I mean we know that the median nerve sits on directly on the
undersurface of the ulu, right?
- If you were to - Be able to, if you on the proximal side
and the distal side to know where to guide your needle to,
to perform hydro dissection of the flexor retina aum,
- Could you point out with the arrow, that big yellow arrow
where the ulu begins deep, I should say from,
let's let's point out I guess the median nerve there
and then where do you see the reticulum begin
and where is its most superficial margin?
- Okay, you get the image that I want.
- Again, I will also remind the audience that this,
the scope of this particular talk is not the advanced
intricacies i I would say of carpal tunnel
advanced procedures.
We will have one of those coming up where a lot
of this anatomy is very much displayed.
The scope of this presentation is where to measure what
to look for the contents of the carpal tunnel.
And that will be one of our next questions, bill, is
where do we measure the median nerve?
So we'll do that next.
- Okay, so where you see the arrow place there is,
is the proximal margin
of the transverse carpal ligament or flexor retina aum.
- Beautiful. - And the distal end is right here if I
rotate the arrow.
So yeah, very easy to define proximal end
and distal end to know where to guide your needle
to if you're entertaining doing
- Yeah, - A an ultrasound guided
hydro dissection of that ligament.
- And let's go on to the measurements bill, could we take,
take that 19 megahertz
for spin on those levels real quick?
Sure. And maybe we'll do an inlet and,
and just use your arrow to show what we're measuring.
I think the cursor and the dotted is gonna be,
although I think on your manual trace it shows up pretty
nice on the, so
- Yeah, we can do that.
Sure. Okay.
So we don't wanna have our depth set to
where we can see the radius
and the ulna to be sure that we're looking
at the pronator quadratus, right?
So here I'm too low,
there're I'm too high, right?
We're, we're proximal pronator quadratus.
We're looking for those longitudinally oriented fibers,
muscle fibers, that penate pattern that you get
when you're long axis to muscle.
So at that level we want to get a good image
of our median nerve.
Bring our depth as such.
It's pronated quadratus, you can see it deep there.
Bring up my measurement tool.
We'll do a trace,
oh I'm sorry.
Didn't do the trace. I'm going to, let's try that again.
Daniel, bear with me.
- Yeah, I noticed that the, the regular ellipse is kind
of hard to see on a zoom call,
but that manual trace leaves a solid white line
and I've come to appreciate it where I,
I actually started drawing things on the machine.
Now with that, when I'm drawing a picture
around some anatomy, I really like the manual trace
hard line definition on the, so ofcy px, you don't see
that in all the systems.
They, they all a lot of times stay dotted
and you know, can be hard
to convey over a live demonstration on
the internet for example.
But beautiful trace there Bill, so
- There, there you have a trace of it that's proximal,
that's at the level of the pronator quadratus.
So we'd save that image unfreeze.
- And could you point out the pronator quadratus in
that last view real quick?
That's a question in the portal there.
- Yep. Let me freeze pronator.
Quadratus is this structure right
here bridging the gap between the radius,
bridging the gap between the radius
and the ulna on here radius here.
See how the fibers of the muscle are longitudinally oriented
as opposed to this short axis more starting eye view
that you get of muscle and your short axis to muscle.
So we have the pronator quadratus bridging the gap
of the radius to the ulnar from here
to here, top to bottom
and then the median nerve
between the flexor muscle bellies here.
So this is the level that you'd wanna freeze your image
and then get a measurement
that answer that.
- That was perfect. Okay.
Now we measure the inlet view, I think next,
- The second level is coming down distally
we see following the median nerve, we see it coming out of
that flexor tunnel.
More superficial now.
Right now it's immediately deep to the
omi longest tendon.
- Could we switch hands? - It's very small in,
in my model right here.
And then we have flexor reac the median nerve
that come over medially.
We wanna establish the level of the sca scaphoid,
FCR te offor
and we're going to give ourselves more depth.
We can even use the
zoom feature if we wanted to,
but I don't think we need to with this transducer
- One request bill, I, I hate
to make you do this mid stride,
but could you switch hit for us
and go lefty so we can see your probe
placement? Is that still possible?
- Oh yeah, I'm sorry, yes,
I'm at the distal wrist crease.
- I see that. Okay. Okay. Yep.
- Yeah, so there's a scaphoid, right? Yep.
- Nice. - FCR median nerve flexor retina aum.
- Let's use that big arrow if you could.
Sorry, that'd be hard to point
with your crisscross your arms though, I guess
- That's okay. Piece of form here.
- Okay,
- On your nerve and artery,
- Beautiful - Working over medium nerve
flexor tendons.
FPL scaphoid, FCR
and right there is where we would then freeze our image
and,
and trace
the median nerve at its entry.
What not To backtrack a little too much coffee this morning.
- Well, not to mention you're crisscrossing your
arms. Thank you for doing that.
- No worries. There we go.
And there we have measurement down at,
down in the carpal tunnel.
- Now what I'm gonna do for the attendees is just thank
everybody for being here
and for this webinar we're gonna conclude that
as the main recording and,
and I'm checking the chat window
for any last minute questions.
But for the sake of time, I do wanna go ahead
and make sure that we have a great stopping point
for the recording so that we can start getting that edited
and posted on the Sono Site Learning Institute.
If you go back to sono site.com, watch
for the rotating banner
and you'll see a webinars link come up to register
for future webinars.
But Bill, I just wanna thank you so much for
that wonderful demonstration, man, we've, we've seen a lot
of anatomy today, but with the 19 megahertz probe,
it's like a macro lens.
I've, I've gotta say it's probably the star of the show.
Counting Fales is
what we look like we can see right there on the screen is
just stunning, not to mention the driver.
Great job, bill. Thank you everybody for your time today.
We're gonna, we're gonna stop the recording at this.
Learn diagnostic ultrasound techniques for the carpal tunnel area including best practices, during this expert-led, live webinar.
What You'll Learn
- Review the anatomy within the carpal tunnel region including bones, tendons, ligaments, and the median and ulnar nerve
- List indications for an evaluation of the carpal tunnel
- Discuss possible pathology to look for such as median nerve entrapment and flexor tendinopathies
Daniel Shelton, RT(R) is the Director of Musculoskeletal Market Development for FUJIFILM Sonosite. Daniel spent 18 years as a dedicated musculoskeletal sonographer and 12 of those years have been here at Sonosite. He now leads musculoskeletal market development, where he works to spread the word about the benefits of point-of-care ultrasound.
This educational webinar is intended for healthcare professionals and not for patients or consumers. The material is provided for general educational purposes, as a reference and a supplement to professional experience, education and training, and should not be considered the exclusive source for this type of information. This educational webinar is not intended to recommend any device for a particular indication or to provide indications for use for any device. At all times, it is the professional responsibility of the practitioner to exercise independent clinical judgment in each particular situation. Fujifilm assumes no responsibility or liability for any misuse of the information imparted in this webinar. This educational webinar does not supplement, replace, or supersede device labeling, including instructions for use, which accompanies any FUJIFILM Sonosite product.