Posterior Mediastinum

Question 1

Is it easy to view?

Answer 1

No because anything you image anteriorally will be blocked by theheart

Question 2

Azygos System of Veins

Answer 2

Runs up both sides of the vertebral column posteriorally. Eventually runs into SVC, provides an alternative pathways used in some diseases
eg) portal hypertension

Question 3

Where would you find the Azygos Vein? Starts?

Answer 3

Right paravertabral region.
Starts: Where right subcostal vein meets right ascending lumbar vein.

Arches up and over, and drains into the SVC

Question 4

Hemiazygos vein? Starts?

Answer 4

Opposite to azygos vein, on the left hand side of vertebral column.

Starts: where L subcostal vein meets Left ascending lumbar.

Drains into azygos

Question 5

Accessory hemiazygos

Answer 5

Also left side, drains into azygos, smallest of the 3

Question 6

Draw normal azygos drainage and then compare to portal hypertension

Answer 6

…

Question 7

What happens in portal hypertension?

Answer 7

Blood cannot get to the liver from the stomach, the issue is with the portal vein.
As veins to the viscera have no valves, blood can flow either direction. So in portal hypertension blood goes in the opposite direction, lots of little oesophageal veins fill and become engorged. (oesophageal varices)
This is important as it means blood doesn’t hit a ‘roadblock’

Question 8

Oesoophageal varcies?

Answer 8

Occur portal portal hypertension, veins become tortuous and large. Dangerous as that tissue is not made to be that stretched, and bleeds can occur.

Question 9

Apart from oesophageal varcies, where else does blood get shunted in portal hypertension?

Answer 9

Rectal varices

Caput medusae

Question 10

Thoracic Duct

Answer 10

Runs up midline, normal flat and hard to find unless filled with ‘stuff’.
Small, looks like a vein.
Drains ALL lympahtic fluid from abdomen, upper+lower limbs.
Exception: right arm and some of face.

Question 11

Where does the thoracic duct start, cross and finally drain into?

Answer 11

Starts as cisternae chyli, runs up posterior midline and crosses left at ~T5.
Pops up in left supraclavicular region, where it drains into the azygos sytem where L.subclavian and L.internal jugular meet.

Question 12

How does the thoracic duct stop venous blood getting through where it drains?

Answer 12

A valve

Question 13

3 regions where Oesophagus gets compressed?

Answer 13

1) Where aorta arches up and over (in aortic aneurysm)
2) Where the Left main bronchus compresses ( lung cancer or growth)
3) Eosophageal Hiatus (**useful as physiological sphincter)

Question 14

Nerve Supply to the oesophagus

Answer 14

PS: vagus
Sympathetic: Sympathetic trunks

Question 15

Arterial/venous supply of oesophagus

Answer 15

Differing art/venous supply at top and bottom

Artery
Sup: aorta
Inf: Left Gastric

Vein
Sup: Azygos system
Inf: Left gastric > portal system

Question 16

Barium swallow?

Answer 16

Done to diagnose oesophageal issues

Question 17

Draw extensive arterial system

Answer 17

…

Question 18

Radioradial delay

Answer 18

Take radial pulse on both sides, check they’re the same

Question 19

Radiofemoral delay

Answer 19

Check radial pulse relatice to femoral

Question 20

What could cause a radioradial or radiofemoral delay?

Answer 20

Coarctation of the aorta. Usually occurs around where ductus arteriosus is/has closed off. Tissue is similar to to DA but has extended out.

Can still happen anywhere around aorta

Before DA: incompatible
During: iffy
After DA: still get some bloodflow, may not get picked up for ~6weeks

Question 21

Two ways to get past a coarctation

Answer 21

1) increased bloodflow to anterior intercostals (as the connect to posterior IC)
2) increased bloodflow to superior epigastric as it “buddys” with the inferior epigastric > external iliac > femoral artery

Can occur as arteries don’t have valves