0:00

This is one of these areas that are a little bit

0:03

complex and tricky, but can be identified if you

0:06

understand the anatomy of the brachial plexus,

0:09

the thoracic inlet, and the thoracic duct.

0:12

So, when we look at structures at the base

0:14

of the neck, we have this structure,

0:18

which is ascending, which is the thoracic duct.

0:21

The thoracic duct then extends

0:23

into the base of the neck and does

0:25

this curve, this 180-degree curve.

0:28

At this level, the thoracic

0:29

duct receives tributaries from

0:31

multiple other lymphatic trunks.

0:34

They include the left jugular lymph

0:36

trunk, the left subclavian trunk, and

0:38

also a mediastinal component as well.

0:41

This confluence of the various tributaries,

0:43

with the largest tributary being the thoracic

0:46

duct, is located at the thoracic inlet,

0:50

just at the junction between the internal

0:51

jugular vein and the subclavian vein.

0:54

So sometimes we can see abnormalities

0:57

involving the left thoracic inlet that represent

1:00

abnormalities of the lymphatic drainage,

1:04

and specifically in the region where the

1:06

thoracic duct drains into the subclavian vein.

1:10

So, these are images of a non-contrast

1:13

T1-weighted image on your left, and

1:15

also a T2-weighted image on the right.

1:18

So, on the left-hand side, what we'll

1:20

do is we'll scroll through these images.

1:23

So what we see here is a round

1:24

structure that's intermediate signal

1:26

on T1 and is high signal on T2.

1:30

This structure is directly

1:32

adjacent to the internal jugular vein.

1:34

And when we scroll inferiorly, we can see

1:36

this small component that's actually extending

1:39

posteriorly to the internal jugular vein.

1:42

This is in the location of the thoracic

1:44

duct, just cephalad to where the thoracic

1:48

duct drains into the subclavian vein.

1:51

When we look at the normal components anteriorly,

1:53

we can see the anterior scalene muscle and

1:56

the other structures of the thoracic inlet,

1:58

and just posterior to this is the brachial plexus.

2:02

So what this likely represents is a small

2:04

dilatation of the thoracic duct and the

2:07

lymphatic components, representing a small

2:10

chylecele that's adjacent to the internal

2:12

jugular vein and within the thoracic inlet.