0:01

We talked about the investing

0:03

fascia of the carotid space,

0:05

but what about the contents of the carotid space?

0:08

Well, clearly the most important things that we see within

0:12

the carotid space that are visible on CT and MRI

0:15

are the carotid artery and the jugular vein.

0:18

And the carotid artery, by and large, is medial

0:21

to the jugular vein in most cases.

0:27

In addition,

0:28

there are lymphatics and lymph nodes that

0:30

are adjacent to the carotid space.

0:33

And within the carotid space, we

0:35

also see cranial nerves IX, X,

0:38

XI, and XII early on in the carotid space

0:42

as we are scanning from top to bottom.

0:45

However, as we extend further inferiorly, the 9th,

0:50

11th, and 12th cranial nerves peel off to the various

0:55

structures of the pharynx as well as the tongue.

0:58

However, the vagus nerve is the nerve that extends from

1:03

the suprahyoid to the infrahyoid space.

1:07

Posteriorly along the sheath,

1:10

the carotid sheath, is the sympathetic

1:12

nervous system plexus.

1:13

So we see that is usually defined along the

1:16

posterior margin of the carotid sheath.

1:19

And the ansa cervicalis,

1:20

which obviously is high up in the neck

1:23

at the C1 to C3 level,

1:25

is found along the anterior margin

1:28

of the carotid sheath.

1:30

So these are the critical structures that are

1:32

enclosed within the carotid sheath and therefore

1:35

the pathology, as you would expect,

1:37

have to do with the vessels,

1:40

the cranial nerves, and the lymphatics.

1:45

As I said,

1:46

the carotid space goes from the skull

1:49

base down to the mediastinum.

1:51

So it is one of the spaces that extends

1:53

from suprahyoid to infrahyoid.

1:57

And it is also termed the poststyloid parapharyngeal

2:00

space, defined by being behind the styloid process,

2:04

the posterior belly of the digastric

2:06

and the styloid musculature,

2:09

the dominant ones being the stylohyoid muscle,

2:12

the styloglossus muscle, and the

2:13

stylopharyngeus muscle.