0:00

Okay,

0:01

so we've gone over the parotid gland and the parotid duct.

0:05

I showed you some pathology associated with the parotid

0:09

duct, including the calculus and the sialocele,

0:13

and also showed you some pathology as far as the

0:15

innervation of the facial...

0:17

of the parotid gland,

0:18

which is predominantly by the facial nerve

0:21

and the auriculotemporal nerve,

0:22

although we do see some branches of the 9th cranial nerve

0:25

also innervating the parotid gland.

0:28

So let's move from the parotid gland

0:31

and to the submandibular gland.

0:33

This is the second largest of the major salivary glands,

0:37

and this is a little different than the parotid gland

0:40

in that its saliva tends to be more viscous,

0:42

more mucous saliva.

0:44

It contributes about 40% of the saliva in a day.

0:48

The gland weighs about ten to 15 grams,

0:51

and it has arterial supply by facial and lingual arteries

0:55

and nervous supply by the lingual nerve, the chorda tympani,

0:59

which is a branch of the 7th cranial nerve

1:02

and the sympathetic nervous system.

1:06

We refer to the submandibular triangle,

1:09

the superior border of which is the body of the mandible

1:12

and the anterior border of the anterior belly,

1:15

the digastric.

1:15

And this creates sort of this triangular area,

1:18

which is bordered posteriorly

1:20

by the posterior belly of the digastric.

1:22

And within this submandibular triangle,

1:25

one has the submandibular gland.

1:27

But you may occasionally also see lymph nodes in the

1:32

submandibular triangle, and that's usually on an

1:36

inflammatory basis or you can see

1:38

it on a neoplastic basis.

1:40

And we're going to be talking again about the deep portion

1:43

of the submandibular gland and the superficial portion

1:47

of the submandibular gland.

1:48

Now, by superficial,

1:50

we're talking about superficial to the skin surface

1:53

and therefore, the portion of the gland that is

1:56

actually below the mylohyoid muscle,

1:58

which I'll demonstrate, is considered superficial,

2:02

whereas that portion that is deep to the,

2:06

and above the mylohyoid muscle in the floor of the mouth

2:09

is considered the deep portion.

2:14

So here is a diagram which shows us that mylohyoid muscle.

2:21

And this is that plane of the mylohyoid muscle.

2:25

And we have portions of the gland which are going to be

2:29

above it and portions of the gland

2:31

that are going to be below it.

2:33

The portion of the gland below it and close to the skin

2:37

surface is considered the superficial

2:39

portion of the submandibular gland,

2:41

whereas the portion above the mylohyoid muscle coursing

2:44

up here is going to be the deep portion.

2:48

And there is this little area posterior to the mylohyoid muscle,

2:52

which we sometimes we refer to as the boutonniere,

2:54

where the glandular tissue communicates.

2:58

This diagram also shows you the sublingual gland,

3:01

which is going to be also in the floor of the mouth region

3:05

and may abut the deep portion of the submandibular

3:10

gland more posteriorly.

3:12

The gland has a close association

3:15

with the anterior facial vein,

3:19

which is seen coursing here.

3:22

This is our internal jugular vein.

3:25

It continues here in our retromandibular vein,

3:28

which is associated with the parotid gland.

3:33

And then as we look at the submandibular gland,

3:36

you see that the anterior facial vein,

3:39

by and large, is superficial to the

3:43

submandibular triangle structures,

3:45

which include the gland and some lymph nodes.

3:50

Here we have a CT scan demonstrating the superficial

3:56

portions of the submandibular gland.

4:00

So here is the submandibular gland.

4:04

And here's the submandibular gland,

4:06

generally will show some

4:07

element of contrast enhancement.

4:09

And you notice that there is that vein which courses

4:13

just superficial to the submandibular gland,

4:16

which is the anterior facial vein.

4:19

The anterior facial vein will be useful in identifying

4:22

those masses which are outside

4:24

the gland superficial to it,

4:27

generally lymph nodes, from those masses that are

4:31

within the gland. In this specific case,

4:35

we see an area of abnormal density within the superficial

4:40

portion of the right submandibular gland,

4:43

which represented a mass,

4:45

and this ended up being a mucoepidermoid carcinoma.

4:51

Mucoepidermoid carcinoma is the second most common

4:54

cancer to involve the submandibular gland.