0:00

Another example here, the sagittal imaging plane.

0:04

There's your sesamoid.

0:05

We would like to see that nice thick,

0:07

robust ligament extending from the saam to the base

0:11

of the proximal phalanx.

0:12

Here you can see that it's at least moderate grade, 50%,

0:15

perhaps slightly more torn high signal intensity around it,

0:19

and maybe even a little bit

0:21

of high signal intensity here within

0:23

that flexor digitorum brevis.

0:25

We're gonna go over that in greater detail.

0:27

But remember, your sesamoids reside in the medial

0:30

and lateral heads of the flexor digitorum brevis.

0:34

Of course, as you're assessing the sesamoids, you're going

0:37

to look for their osseous integrity.

0:39

Uh, it you can also have failure in this area

0:41

by having sesamoid fractures

0:43

or osteochondral injury there as well.

0:50

So now let's look at that musculo tendonous syn the system.

0:54

So remember, we've got our sesamoids,

0:56

and we already said that the sesamoids are going

0:59

to re reside in the two heads medial

1:01

and lateral of the flexor lysis brevis.

1:04

We've got our flexor lysis longest. You're halfway there.

1:07

And then what you're going to look at is on the adductor

1:11

and abductor side of the articulation, the abductor lysis

1:15

and the adductor lysis.

1:17

So simple. It seems like it's very complex,

1:20

but when you start to just understand the nomenclature in

1:23

the anatomy there, it becomes very easy to book.

1:27

Keep those different areas.

1:29

So take a look at this illustration here.

1:31

We're looking at the plantar aspect of the first MTP.

1:35

Your sesamoids are here.

1:37

So those are gonna be the two heads

1:38

of the flexor digitorum brevis.

1:41

Remember the longest is going to come superficial.

1:44

And then of course you're gonna have the abductor

1:47

and adductor paralysis.

1:49

And then if we think about the long axis images here,

1:52

here are your OIDs.

1:54

Those are gonna be your landmark for the two heads

1:57

of the flexor digitorum brevis,

1:59

the longest we're seeing here with the asterisk.

2:02

And then as you look at the medial

2:03

and lateral sides of the MTP, you'll be able

2:07

to identify the abductor and the adductor.

2:11

One more example with the next set of images, again,

2:14

being able to, at sesamoid ligament,

2:17

remember the sesamoids residing in the FDB.

2:21

Of course, we're already more, more, uh, superficial,

2:24

so we're not seeing very well, um, the flexor Hal as long

2:28

as, and then your abductor in your adductor reinforcing both

2:31

sides of that articulation.

2:33

So you're getting this idea

2:35

that when we move from the sesamoid complex, we have that

2:39

intrinsic stabilization, the static stabilizers,

2:42

the muscular tendus area, dynamic stabilization.

2:46

This is a pattern that you see in every single articulation

2:50

as you move throughout the body.

2:51

You have the osseous alignment,

2:53

you have static stabilization,

2:55

and then you have dynamic stabilization.

2:58

A lot of times we, I think forget

3:00

and underestimate the importance of the dynamic

3:03

stabilization, but it's super, super important.

3:06

And when you start to have abnormalities

3:08

or a failure of the dynamic stabilizers, you see that

3:11

that puts more emphasis, um, more responsibility, so

3:16

to speak, on your static stabilizers.

3:18

So things get out of balance,

3:19

and then one thing starts to fail.

3:20

The next thing starts to fail,

3:22

and it, it's sort of a cascade.

3:24

So being able to identify those, um, very important.

3:29

So looking in the sagittal imaging plane here,

3:32

look at the high signal intensity here within the muscle.

3:35

So you're following from the sesamoid back to the muscle.

3:39

And of course, remembering again that medial

3:41

and lateral sesamoids reside in the medial

3:44

and lateral heads of the flexor digitor revis.

3:47

So this has been reported, uh, in the literature.

3:51

So just an example here of what we're looking for

3:55

as we assess and survey the first MTP.

3:58

So the sesamoid system looking here, sesamoid

4:02

with the sesamoid phalanx ligament, the sesamoid

4:07

to metatarsal ligament.

4:08

The inters ligament in this case,

4:12

as you think about that plantar plate, remember

4:15

that's gonna be, um, more closer to the articular surface

4:20

of the metatarsal

4:21

and extending from, uh, again, the sesamoids to the phalanx,

4:26

probably again, the least important stabilizer,

4:28

but something that can certainly cause pain or dysfunction.

4:32

And then looking in this case at the flexor lysis longus

4:36

here, look at the torn ends.

4:39

The secondary finding here

4:40

that helps you identify this is the high signal intensity,

4:44

superficial in this case to the sesamoid complex, uh, here

4:48

and the sesamoid flange ligament, high signal intensity,

4:51

two torn ends of the flexor lysis longest

4:54

with pretty significant gap.

4:56

In this case, it gets a little bit tricky

4:58

because when you're looking at the torn end here,

5:00

you've got altered signal intensity.

5:02

So you're trying to distinguish what exactly is going on.

5:05

But look for the high signal intensity in this case,

5:08

following these structures

5:09

to their ultimate site of attachment.

5:12

To be able to identify any abnormalities here.

5:17

Look at the plain film In this case, you know,

5:19

this is something that, you know, once you're looking

5:22

for it, it becomes so obvious.

5:23

But as you're looking at foot films,

5:25

you're really not always thinking about, gosh,

5:26

my sesamoids should be at a specific location.

5:30

In this case, I think it's a little bit easier to identify

5:33

because you see

5:34

that the lateral sesamoid has more proximal position than

5:37

the medial sesamoid.

5:39

Looking on the lateral film, we see that proximal migration,

5:42

that is an excellent clue that you've got an abnormality of

5:46

that plantar plate complex of the great toe.

5:50

So let's look at another case of pathology, sagittal images,

5:54

those super nice to be able to look at the

5:56

Position of the sesamoid.

5:58

Look at the integrity of sesamoid phalangeal ligament.

6:01

Clearly abnormal.

6:02

Here you've got areas of focal moderate

6:05

to high grade discontinuity from the sesamoid.

6:08

Here, this thing has high signal intensity within the

6:11

substance following back the oid

6:14

to metatarsal ligament in this case,

6:16

also irregular in its appearance.

6:19

Inter saam ligament in this case intact.

6:22

We're looking for the area here that is closer

6:25

to the articular surface, irregular in nature.

6:28

No surprise there. As you start

6:30

to have these capsular structures

6:32

with inflammatory changes can look irregular and thickened.

6:36

As we move over to the medial side here,

6:39

looking at the sesamoid to flange ligament,

6:42

not completely normal, right?

6:43

You're seeing altered signal intensity

6:45

with ary partial tearing here as you look at the metatarsal

6:50

to f uh, sesamoid ligament, slightly irregular but intact.

6:54

And then moving back here,

6:56

following from the sesamoids proximally.

6:59

Remember the heads of the, the flexor lysis, brevis,

7:03

high signal intensity here, um, with some muscle edema.

7:07

So while it seems like those 15 structures

7:11

are not approachable, if you try to list them out,

7:14

when you start to really kind of break it down into saam,

7:19

capsular, and musculotendinous areas to assess,

7:22

it becomes totally approachable, uh, in your ability

7:25

to provide a very detailed analysis.

7:29

Um, I think is super helpful in the characterization.

7:32

Very important.