0:00

I'd like to use this case to show the anatomy of the

0:04

submandibular gland, and also to introduce

0:07

you to Wharton's duct.

0:10

So we are looking at a CT scan of the neck,

0:14

which is performed with 2.5 mm thick sections.

0:17

And we're going to go inferiorly because this

0:20

patient had discomfort in the left floor of the mouth.

0:24

So as we go down,

0:25

we're obviously having issues with the

0:27

dental amalgam artifact.

0:29

However, when we get down to the mandibular level,

0:32

we're actually free of that artifact.

0:34

Now there is anatomy here that

0:37

I want to point out to you.

0:40

This is the midline of the tongue,

0:42

and just to the other side of the midline

0:46

fatty septum of the tongue,

0:47

one finds the genioglossus muscles.

0:51

These are the largest of the extrinsic

0:54

muscles of the tongue.

0:58

There is another curving

1:02

muscle here that you can see on both sides.

1:08

So this is a muscle that you can see faintly here.

1:12

This is our genioglossus muscles.

1:14

Here and here.

1:17

And there is this other muscle,

1:19

which as you can see,

1:21

curves just a little bit here.

1:25

And this is the hyoglossus muscle.

1:30

Remember in our talk on the oral cavity and oral pharynx,

1:33

that you have this muscle that intertwines

1:36

with the styloglossus muscle and we call it the

1:40

styloglossus hyoglossus muscle complex.

1:45

Just lateral to the

1:48

styloglossus muscle, you see intermediate

1:52

low signal intensity tissue.

1:54

That intermediate low signal intensity tissue is the

1:58

sublingual space with the sublingual

2:01

gland in the floor of the mouth.

2:07

Lateral to that,

2:09

we come upon a very important muscle, and this is

2:12

the muscle known as the mylohyoid muscle.

2:15

It's the muscle portion of the floor of the mouth,

2:20

the other portion being the sublingual gland.

2:25

However,

2:25

within this sublingual space

2:27

in the floor of the mouth,

2:28

the other thing that passes is Wharton's duct.

2:33

Wharton's duct

2:36

inserts at the...

2:37

in the floor of the mouth.

2:38

If you lift up your tongue and look in the floor of

2:40

the mouth on either side of the midline frenulum,

2:44

you will find Wharton's duct orifice.

2:49

This patient has a calcification in the

2:53

proximal portion of Wharton's duct.

2:56

Wharton's duct is the duct of

2:58

the submandibular gland.

3:00

So where indeed is the submandibular gland?

3:04

So let's continue to scroll downward.

3:08

And you can see now that we have

3:12

tissue around this huge calcification,

3:15

which represents the residual submandibular gland.

3:21

Here's the submandibular gland on the left.

3:25

Here's the non atrophic,

3:28

it's still kind of small,

3:29

but right submandibular gland.

3:32

This portion of the submandibular gland,

3:35

which is below the mylohyoid muscle

3:38

is considered the superficial portion

3:41

of the submandibular gland.

3:45

And you'll notice that there has been some fatty

3:47

infiltration or atrophy of the left submandibular

3:52

gland by virtue of this huge calcification

3:55

which coursed into

3:58

Wharton's duct.

4:01

As I mentioned,

4:02

there is a portion of submandibular tissue

4:05

which may course posterior to the mylohyoid muscle.

4:11

You can just see on the left...

4:12

on the right side that there's

4:14

just this little bit of tissue.

4:16

Let me use my pen.

4:18

So let's say that this is our mylohyoid

4:21

muscle ending right here.

4:23

And here you have

4:25

submandibular tissue.

4:27

So that portion which courses just medial to

4:31

and above the mylohyoid muscle,

4:33

would be the deep portion of the submandibular gland.

4:36

So it's really dominated by the superficial portion.

4:40

But you can see just a little bit of that tissue

4:42

here, posterior to the posterior border

4:45

of that mylohyoid muscle.

4:48

I want to make another anatomic point

4:52

which is important, just for the sake of the

4:56

anatomy and the pathology.

4:58

So I have been referring to Wharton's duct.

5:06

Wharton's duct is the duct of

5:09

the submandibular gland.

5:11

Do not confuse that with a tumor that

5:14

is exclusive to the parotid gland,

5:17

which is known as Warthin's

5:21

tumor.

5:23

This is not found in the submandibular gland.

5:26

It is a parotid gland, benign tumor.

5:29

So be careful of the wording here.

5:34

The other point I just wanted to make was the

5:37

close proximity that you see between the

5:42

submandibular glandular tissue and the parotid

5:47

glandular tissue. So down here,

5:49

at the angle of the mandible,

5:50

we're at the tail of the parotid gland and

5:52

it comes very close, as you can see,

5:54

to the submandibular tissue.

5:57

There are occasions where you'll have masses that

5:59

might bridge between the two and you question

6:04

which gland is it primarily associated with.